KR20050084166A - Bicomponent strengthening system for paper - Google Patents

Abstract

The present invention is directed to a bicomponent strengthening system and the paper webs produced with the bicomponent strengthening system. Through use of the strengthening system, paper webs may be produced in which the strength characteristics of the web may be specifically tailored. The first component of the system comprises a polymer having at least about 1.5 m-eq primary amine functionality per gram of polymer and a molecular weight of at least about 10,000 Daltons. The second component may be either a polymeric anionic compound or a polymeric aldehyde functional compound. For example, the polyamine polymer component may be a polyvinylamine or polysaccharide having primary amine functionality. In one embodiment, the second component may be a cationic polymeric aldehyde functional compound. For example, the second component may be a cationic glyoxylated polyacrylamide. In another embodiment, the second component may be a polymeric anionic compound comprising carboxy functionality.

Description

Bicomponent Strengthening System for Paper

Generally, in the field of tissue making and papermaking, a number of additives have been proposed for specific purposes, such as increasing wet strength, enhancing softness, or controlling wettability. For example, in the past, wetting agents have been added to paper products to increase strength or otherwise control the properties of the product when used in contact with water and / or in wet environments. For example, a wet enhancer is added to the paper towel so that the towel can be used to wipe or rub the surface without decomposing even after the paper towel is wet. Wet enhancers are also added to facial tissue to prevent the tissue from tearing upon contact with the fluid. In some applications, wetting enhancers are also added to bath tissue to provide strength to the tissue during use. However, when added to bath tissue, the wetting enhancer should not prevent the bath tissue from disintegrating if it is thrown into the toilet and spilled into the sewer. Wet enhancers added to bathroom tissues are often referred to as temporary wet enhancers because they maintain the wet strength in the tissue only for a certain time.

While many advances have been made in providing strength properties to paper products, there are still many demands for increasing the strength properties in certain applications, as well as allowing for the diversification of the strength properties provided by the reinforcement to the paper web.

In the preparation of permanent wetting enhancers, such as the Kymene ^(R ) series from Hercules, Inc., Wilmington, Delaware, chlorinated organic materials are commonly used. For example, epichlorohydrin is generally used as a raw material, and the reaction chemistry used is typically 1,3-dichloro-2-propanol (DCP) and 3-chloro-1,2-propanediol (CPD). Produces other chlorinated organic materials. Many other wet strength materials also include N-chlorinated polymers described in European Patent Application No. 289,823, published November 9, 1988; Aminopolyamide-epichlorohydrin acid resin resins of U.S. Patent No. 5,189,142 issued to February 23, 1993 (Devore et al.) Or U.S. Patent No. 5,364,927 (Devore et al.) Issued November 15, 1994; Or resins of US Pat. No. 6,222,006 (Kokko et al.), Issued April 24, 2001, formed by reaction of epichlorohydrin with an end-protected polyamineamide polymer; Or chlorinated or include chlorine byproducts, such as epichlorohydrin-based resins of Maslanka, issued July 1, 1997. US Pat. No. 5,644,021 (Maslanka).

Recently, there has been increasing interest in removing chlorinated residues from wet-strength paper additives. Methods under consideration include the use of microorganisms and enzymes, as discussed, for example, in the Symposium on "The Role of Biotechnology in Industrial Maintenance" (Antiwerp, Belgium, May 16-17, 2002). The publication described an effort to reduce the chlorinated byproducts, including the use of bacteria that can metabolize such byproducts into less harmful substances. Others have devised other methods to remove some of the chlorinated organic materials often found in wet strength resins. However, given the increasing environmental concerns associated with halogenated organic compounds, there is still a need to reduce or eliminate the use of chlorinated compounds in the production of wet strength resins or wet strength resins.

Summary of the Invention

The present invention relates to a method for producing a paper web comprising the two-component reinforcement system and the two-component reinforcement system, as well as a web produced by the method. In one embodiment, the present invention relates to a paper web in which the strength properties of the web can be specifically tailored by using a two-component strengthening system.

In general, the method of the present invention includes providing a slurry of pulp fibers and treating the fibers with a two-component reinforcement system before forming a web from the fibers. The first component of the reinforcement system comprises a polymer having at least about 1.5 m-eq of primary amine functionality per gram of polymer and a molecular weight of at least about 10,000 Daltons. The second component may be either a polymeric anionic compound or a polymeric aldehyde functional compound.

In one embodiment, the polyamine polymer may have at least about 11 m-eq primary amine functionality per gram of polymer. In another embodiment, the polyamine polymer may have at least about 15 m-eq primary amine functionality per gram of polymer. For example, the polyamine polymer may have a primary amine function of about 10 m-eq or more and a molecular weight of about 20,000 daltons or more.

In one embodiment, the polyamine polymer component may be polyvinylamine. For example, the polyamine polymer may be a polyvinylamine comprising vinylformamide units in which at least about 50% of the vinylformamide units are hydrolyzed to provide amine functionality. In one embodiment, at least about 70% of the vinylformamide units can be hydrolyzed to provide amine functionality. In another embodiment, at least about 90% of the vinylformamide units can be hydrolyzed to provide amine functionality.

In another embodiment, the polyamine polymer component may be a polysaccharide having a primary amine function.

In one embodiment, the second component may be a cationic polymer aldehyde functional compound. For example, the second component may be cationic glyoxylated polyacrylamide. In another embodiment, the second component may be a polymeric anionic compound comprising a carboxyl functional group. In one embodiment, the second component may be carboxymethyl cellulose.

Importantly, the two components are added separately to the pulp slurry, although the first or second component may be added to the slurry before any other, depending on the desired strength properties of the web.

The pH of the slurry can be adjusted during the process. For example, the pH of the slurry can be adjusted to an acidic pH such as about 6 or less in one embodiment. However, in another embodiment the pH may be adjusted to greater than about 6.

The two components can be added to the slurry in any ratio with respect to each other between about 1: 5 and about 5: 1 ratios as needed.

The two-component strengthening system of the present invention can be adjusted to impart temporary or permanent wet strength to the paper web. For example, a two-component strengthening system can provide a temporary wet strength to the paper web so that the paper web can maintain less than about 70% of the initial wet tensile index after it has been soaked in water for about one hour. In one embodiment, the paper web may maintain less than about 60% of the initial wet tensile index after soaking in water for about 1 hour. For example, in one embodiment the two-component strengthening system of the present invention can act as a temporary wet strength agent, and the paper web thus prepared is wet tensile of less than about 2 Nm / g after soaking in water for about 1 hour. It can have an exponent.

In another embodiment, the two-component strengthening system can provide permanent wet strength to the paper web to maintain greater than about 70% of the initial wet tensile index after soaking in water for about one hour. In one embodiment, the paper web may maintain more than about 80% of the initial wet tensile index after soaking in water for about 1 hour.

In general, the process of the present invention provides a slurry of pulp fibers, and then adds a component of the reinforcement system to the slurry of pulp fibers and deposits a slurry of pulp fibers containing the two components onto a forming fabric. And drying the slurry to form a paper web.

In one embodiment, the paper web of the present invention may have a volume of greater than about 2 cc / g. For example, the paper web may have a volume of greater than about 5 cc / g.

The dry tensile index of the paper web may be greater than about 20 Nm / g in one embodiment. In another embodiment, the dry tensile index of the paper web may be greater than about 22 Nm / g. In another embodiment, the dry tensile index may be greater than about 25 Nm / g.

In general, the basis weight of the paper web of the present invention may be any desired basis weight. For example, in one embodiment, the paper web can have a basis weight between about 5 and about 200 gsm.

In one embodiment, the paper web of the present invention may be a multi-layered paper web, and the two-component strengthening system may be added to one or more layers of the web. For example, in one embodiment, a multi-layered paper web can be produced having a layer composed mainly of softwood fibers and a layer composed mainly of hardwood fibers, wherein the two-component reinforcement system is a layer composed primarily of softwood fibers. Is added to.

The paper web of the present invention may be converted and used to form a single layer of paper product, such as a single layer of bathroom, facial or towel product, or they may be a multi layer of paper product, such as a layer of bathroom, facial or towel product. It can be used by overlapping and converting them together to form a. Any number of plies can be used.

In one embodiment, the present invention relates to a method for reducing the amount of chlorinated low molecular weight organic compounds in a waste stream of a paper making process. In this embodiment, the present invention includes removing the addition of chlorinated reinforcement to the paper making process and replacing the chlorinated reinforcement with the two-component reinforcement system of the present invention. For example, in one embodiment, the two-component reinforcement system of the present invention can replace polyamide epichlorohydrin reinforcement in the paper making process.

Definition and test method

As used herein, if a material can retain an amount of water of at least about 100% of its dry weight as measured by a test for the intrinsic absorbent capacity given below (ie, the material is at least about 1 intrinsic absorbent) If a capacitor) refers to as "absorber". For example, the absorbent material used in the absorbent element of the present invention may be at least about 2, more specifically at least about 4, more specifically at least about 7, and even more specifically at least about 10, for example from about 3 to It may have an intrinsic absorbent dose of about 30 or about 4 to about 25 or about 12 to about 40.

As used herein, " papermaking fibers " includes all known cellulose fibers or fiber mixtures comprising cellulose fibers. Suitable fibers for web manufacture of the present invention include cotton, manila hemp, kenaf, sabai grass, flax, African rapeseed, straw, jute, vargas, milkweed floss fiber and pineapple Non-wood fibers such as leaf fibers; And softwood fibers such as northern and southern softwood kraft fibers, and wood fibers such as those obtained from deciduous and coniferous trees, including hardwood fibers such as eucalyptus, maple, birch and aspen trees. Any natural or synthetic cellulose fibers. Wood fibers can be made in high-yield or low-yield form and can be pulped by any known method including kraft, sulfite, high-yield pulping methods, and other known pulping methods. Fibers made from an organosolv pulping process may also be used. Some fibers, up to about 50% dry weight, or from about 5% to about 30% dry weight, may be synthetic, such as rayon, polyolefin fibers, polyester fibers, two-component sheath-core fibers, multi-component binder fibers, and the like. Fiber. Exemplary polyethylene fibers are Pulpex ^(R) available from Hercules, Inc., Wilmington, DE. Any known bleaching method can be used. Synthetic cellulosic fiber types include rayon and all other fibers derived from viscose or chemically modified cellulose with all its modifications. Chemically treated natural cellulose fibers such as mercerized pulp, chemically rigid or crosslinked fibers or sulfonated fibers may also be used. For good mechanical properties to use papermaking fibers, it may be desirable for the fibers to be relatively intact and mostly unrefined or only slightly refined. Although recycled fibers can be used, new fibers are generally useful because of their mechanical properties and free of contaminants. Mercerized fibers, regenerated cellulose fibers, cellulose produced by microorganisms, rayon and other cellulosic materials or cellulose derivatives can be used. Suitable papermaking fibers may also include recycled fibers, fresh fibers or mixtures thereof. In certain embodiments, which may have high volume and good compressive properties, the fibers have at least about 200, more specifically at least about 300, more particularly at least about 400, most particularly at least about 500 Canadian standard degrees of freedom ( Canadian Standard Freeness.

As used herein, “ high yield pulp fibers ” are pulp produced by a pulping process that provides a yield of at least about 65%, more specifically at least about 75%, and even more particularly from about 75% to about 95%. Of paper fiber. Yield is the production of processed fibers in terms of percentage of initial wood mass. High yield pulp is bleached chemical thermomechanical pulp (BCTMP), chemical thermomechanical pulp (CTMP), pressure / pressure thermomechanical pulp (PTMP), thermomechanical pulp (TMP), thermomechanical chemical pulp (TMCP), high yield snow pulp Fight pulp and high yield kraft pulp, both of which contain fibers with high levels of lignin. The characteristic high-yield fibers may have a lignin content of about 1% or more, more specifically about 3% or more, even more specifically about 2% to about 25% by mass. Likewise, high yield fibers may have a kappa number greater than 20, for example. In one embodiment, the high-yield fibers are mainly softwood, or more particularly softwood, such as northern softwood BCTMP.

As used herein, the term " cellulose-based " means any material having cellulose as its main component, specifically about 50% by weight or more of cellulose or cellulose derivatives. That is, the term is cotton, typical wood pulp, non-wood cellulose fibers, cellulose acetate, cellulose triacetate, rayon, viscose fiber, thermomechanical wood pulp, chemical wood pulp, debonded chemical wood pulp, lyocell ) And other fibers formed from cellulose solutions in NMMO, milkweed or bacterial cellulose. Fibers that have not been spun from or regenerated from solution may be used exclusively if desired, or at least about 80% of the web may not contain fibers spun from spun fibers or cellulose solutions.

As used herein, the "volume (bulk)" and "density" as used herein is one, of the sample the oven, unless otherwise stated in the-dry weight, and 7.62 cm (3- inch) 0.34 kPa (0.05 psi) by using a circular platen with a diameter of Based on thickness measurements taken at load. Details regarding thickness measurements and other forms of volume are described below. As used herein, “debonded pore thickness” is a measure of the pore volume at a microscopic level along a portion of the web, which is less sheared with a densified and non-dense or highly sheared portion of the tissue. It can be used to recognize the difference between the parts.

As used herein, the term " hydrophobic " means a material having a contact angle of water in air of at least 90 degrees. In contrast, the term "hydrophilic" as used herein means a material having a contact angle of water in air of less than 90 degrees. The term "surfactant" as used herein includes a single surfactant or a mixture of two or more surfactants. When a mixture of two or more surfactants is used, the surfactants may be selected from the same or different classes as long as the surfactants present in the mixture are compatible with each other. In general, the surfactant may be any surfactant known to those skilled in the art, including anionic, cationic, nonionic and amphoteric surfactants. Examples of the anionic surfactants include, among others, linear and branched sodium alkylbenzenesulfonates; Straight and branched alkyl sulfates; Linear and branched alkyl ethoxy sulfates; And silicone carboxylates such as silicone phosphate esters, silicone sulfates, and those made by Lambent Technologies, Lambcross Technologies, Georgia. Cationic surfactants include, for example, tallow trimethylammonium chloride, and more generally silicone amide, silicone amido quaternary amine, and silicone imidazoline quaternary amine. Nonionic surfactants include, by way of example only, alkyl polyethoxylates; Polyethoxylated alkylphenols; Fatty acid ethanol amides; Dimethicone copolyols, such as dimethicone copolyol esters, dimethiconol esters, and those made by Lambent Technologies; And composite polymers of ethylene oxide, propylene oxide and alcohols. One exemplary class of amphoteric surfactants is the silicone amphoteric compound, a product of Ramvent Technologies (Norcross, Georgia).

As used herein, often referred to as a "debonder," a "softener" may be used to enhance the softness of a tissue product, which may be introduced with the fibers before, during, or after dispersion. The softener may be sprayed, printed or coated onto the wet web after formation of the web, or added to the wet end of the tissue machine prior to formation. Suitable emollients include fatty acids, waxes, quaternary ammonium salts, dimethyl dihydrogenated uji ammonium chloride, quaternary ammonium methyl sulfate, carboxylated polyethylene, cocamide diethanol amines, coco betaine, sodium lauryl sarcosinate, partially ethoxy Silicified quaternary ammonium salts, distearyl dimethyl ammonium chloride, polysiloxanes, and the like. Examples of suitable commercially available chemical softeners include Verocell 596 and 584 (quaternary ammonium compounds) from Eka Nobel Inc. and Adogen 442 from Sherex Chemical Company. , Quasoft 203 (quaternary ammonium salts) from Quaker Chemical Company, and Arquad 2HT-75 (dihydrogenated Uji dimethyl ammonium chloride, product from Akzo Chemical Company) ) Can be mentioned without limitation. Suitable amounts of emollient will vary primarily depending on the species selected and the desired result. The amount can be, but is not limited to, about 0.05 to about 1 weight percent, more specifically about 0.25 to about 0.75 weight percent, and even more specifically about 0.5 weight percent based on the weight of the fiber.

Unless otherwise specified, tensile strength is a Tapi Test Method for tissues, modified to use a tensile tester with 3-inch tong width, 4 inch full length, and a crosshead speed of 10 inches per minute. It is measured according to T 494 om-88. The wet strength folds the tissue sample so that there is no fold around the centerline of the sample, secures both ends, and soaks the central part of the sample by soaking it in deionized water for about 0.5 seconds to a depth of about 0.5 cm. The absorbent towel is contacted for about 1 second to remove excess droplets of fluid, and the sample is measured in the same manner as the dry strength, except that the sample is unfolded and fixed in the tensile tester tongs and tested immediately. Samples were conditioned under TAPPI conditions (50% RH, 22.7 ° C.) before testing. In general, five samples are combined for the wet tensile test to ensure that the load cell reading is within the correct range. Unless otherwise specified, the drying and tensile properties of machine-fabricated webs are measured in the machine direction of the web.

Tensile index (TI) is a measure of standardized tensile strength with respect to the basis weight of the web tested in both dry and wet conditions. Tensile strength is obtained by converting the tensile strength measured in units of gram force per 3 inch into units of N / m and dividing the result by the basis weight in grams per square meter of tissue to obtain a tensile index in units of Nm / g. It can be converted into a tensile index.

The wet / dry TI ratio (% wet / dry TI) is the wet TI divided by the dry TI and multiplied by 100.

% Wet TI 1-hr is the ratio of wet TI maintained after 1-hour soaking to TI immediately after wetting. This is a measure of wet strength permanence. For the purposes of the present disclosure, a temporary wet strength agent is defined herein as a strength agent that loses at least about 30% of wet TI after 1 hour, ie, less than about 70% of% wet TI 1-hr.

Maximum elongation (%) is the percent elongation in dry state at maximum load during the tensile strength test.

TEA (J / m ² ) is the total energy absorbed in dry at full load during the tensile strength test.

Elastic modulus E (kg _f ) is the elastic modulus measured in the dry state and is expressed in units of kilogram force. A Tapi conditioned sample with a width of 3 inches is placed on the tensile tester forceps at 2 inches of gauge length (full length between the forceps). The forceps are moved away from the crosshead speed of 25.4 cm / min, and the slope is the least square fit of the stress value data of 50 gram force to 100 gram force, or 100 gram force to 200, whichever is greater. It is determined by the least square feet of the stress value data of the gram force. If the sample is so weak that it cannot rupture and withstand the stress of at least 200 gram forces, additional folds are added repeatedly so that the multi-ply sample does not rupture and withstand at least 200 gram force.

The complete and enabling disclosure of the present invention, including the best mode for those skilled in the art, is more particularly described, including reference to the accompanying drawings in the remainder of this specification.

1 is a table describing the physical properties of exemplary polyvinylamines suitable for the two-component strengthening system of the present invention.

In general, the present invention relates to novel two-component reinforcement systems for paper webs that can be tailored specifically to meet the reinforcement requirements of paper products. More specifically, the first component of the reinforcement system is a polymer containing a primary amine functional group, and the second component is one capable of complexing and / or reacting with the first component to form a reinforcement system in the paper web.

In the process of the present invention, the first and second components are added separately to the slurry of pulp fibers to improve the strength properties of the web formed from the pulp fibers. Many process variables can be varied in forming the two-component strengthening system so that the strength properties of the formed paper web can be specifically tailored to the design specifications. For example, the strength properties of the paper web may vary depending on which component is first added to the pulp slurry. Strength properties also include, among other possible variables, the pH of the pulp slurry, the amount of amine functional groups contained on the first component, the molecular weight of the first component, the specific amine-containing polymer used, the functional group of the second component, and the ionic nature of the second component. However, it may vary depending on the nature of the bond formed between the two components.

The two-component strengthening system of the present invention can be tailored to have particular dry strength properties as well as special wet strength properties. Particularly advantageous is that the two-component strengthening system of the present invention can be tailored to be either a temporary wet strength agent or a permanent wet strength agent as needed. For example, in one embodiment, a two-component strengthening system can be tailored to act as a permanent wet strengthening agent, thereby obviating the use of previously known wet strengthening agents. This is particularly advantageous in embodiments where a two-component strengthening system is used to replace the conventionally used wetting enhancers known to increase levels of contaminants, especially low molecular weight organic chlorinated compounds, in the wastewater of the papermaking process.

According to the present invention various different primary amine polymers and chemical compounds may be combined. Examples of suitable primary amine-containing polymers include various polyvinylamines, polysaccharides having primary amine functional groups, and the like. Suitable materials for use as the second component in the two-component strengthening system include polymeric anionic compounds, polymeric aldehyde functional compounds, surfactants, mixtures thereof, and the like.

Cellulose webs made according to the present invention can be used for a wide range of applications. For example, products made in accordance with the present invention include tissue products such as facial tissues or bath tissues, paper towels, wipes and the like. Webs made according to the invention can also be used in diapers, sanitary napkins, wet wipes, composites, molded paper products, paper cups, paper plates and the like.

The present invention is now discussed in more detail. Each component used in the present invention is discussed first, followed by the method used to form the two-component strengthening system and the paper product according to the present invention.

Polymers with Primary Amine Functional

The first component of the present invention may be any polymer having a suitable amount of primary amine functionality, suitably combined with a high molecular weight. In particular, the first component of the reinforcement system should have at least about 2 m-eq primary amine per gram of polymer. For example, the first component may have greater than about 11 m-eq primary amine per gram of polymer. In one embodiment, the first component may have at least about 15 m-eq of primary amine per gram of polymer, for example about 19 m-eq per gram of polymer, or greater amounts of amine functionality.

In addition, the first component should have a molecular weight of at least about 10,000 Daltons. For example, in one embodiment the first component may have a molecular weight of at least about 20,000 Daltons and at least about 10 m-eq primary amine per gram of polymer. Although polyamine compounds having any practical molecular weight range can be used, suitable polyamine compounds can, in certain embodiments, have a molecular weight range of about 10,000 to 1,000,000 Daltons. For example, the polyamine polymer may have a molecular weight range of about 5,000 to about 5,000,000, more specifically about 20,000 to about 3,000,000, most particularly about 50,000 to about 500,000. For example, polyamines having a molecular weight of about 50,000 to about 300,000 and a molecular weight of about 40,000 to about 750,000 can be used.

Possible primary amine-containing polymers include polyvinylamine, polyallylamine, polyethyleneimine and the like. In one embodiment, the first component of the invention may comprise a polysaccharide having a primary amine function.

In general, any suitable polyvinylamine can be used in the present invention. For example, the polyvinylamine polymer can be a homopolymer or a copolymer.

Useful copolymers of polyvinylamine include those prepared by hydrolyzing polyvinylformamide to varying degrees to obtain copolymers of polyvinylformamide and polyvinylamine. An exemplary material is the Catiofast ^(R ) series available from BASF, Ludwigshafen, Germany. 1 describes the physical characteristics of several different catiofast ^(R) polyvinylamines that may be suitable as the first component of the two-component strengthening system.

The degree of hydrolysis of the polyvinylamine used in the system formed by hydrolysis of polyvinylformamide, copolymers of polyvinylformamide or derivatives thereof may be about 10% or more, and an exemplary range is about 30% to about 100%, or about 50% to about 95%. Characteristics of exemplary polyvinylamines formed by hydrolysis of polyvinylformamides are described in the table below.

Mol% vinylamine Mol% vinylformamide Repeat Unit Mw M-eq primary amine per gram of polymer 90 10 45.8 19.7 80 20 48.6 16.5 70 30 51.4 13.6 60 40 54.2 11.1 50 50 57 8.8 40 60 59.8 6.7 30 70 62.6 4.8 20 80 65.4 3.1 10 90 68.2 1.5

Polyvinylamine compounds that can be used in the present invention include copolymers of N-vinylformamide with other groups such as vinyl acetate or vinyl propionate, wherein at least some of the vinylformamide groups are hydrolyzed. Copolymers of polyvinylamine and polyvinyl alcohol may also be used.

Other polymers with primary amine functional groups may be used. One exemplary polysaccharide having a primary amine function that can be used in the first component of the invention is chitosan, which is an amine-containing polysaccharide expressed from chitin, a naturally occurring polysaccharide extracted from recycled crabs or shrimp shells. Like many other possible components suitable for the present invention, chitosan does not add chlorinated organic compounds to the wastewater stream of the papermaking facility and is safely biodegradable.

Polymeric anionic compounds

As described above, according to the present invention, the polyamine polymer may be sequentially combined with the second component in the pulp feed, after which the two-component strengthening system may be expressed. In one embodiment, the polyamine polymer can be combined with a polymeric anionic compound. When added to the pulp feed sequentially, the polyamines and polymeric anionic compounds not only enhance strength, such as wet strength, but also process parameters and special components are tailored to provide the surface chemistry and wettability of the web formed from the pulp feed. It can provide improved control over.

Conventionally, polymeric anionic compounds have been used for wet strength applications. However, the combination of polymeric anionic compounds and polyamines in the pulp feed has given unexpected benefits and advantages. For example, pulp treated with only polymeric anionic compounds can have a slight increase in wet strength. Likewise, webs treated with polyamines such as polyvinylamine will show an increase in wet strength. However, the sequential addition of two components, the polymeric anionic compound and the polyamine polymer, to the pulp feed not only results in improved wet and dry strength, but also provides specific properties of the paper web produced by the process. It was found that it could be tailored. Thus, according to the present invention, by changing the process parameters while using the same or different components in the reinforcement system, the specificity of the wet strength, dry strength, the degree of wet strength maintained over time (durability of wet strength), etc. It has been found that the value can be changed.

This effect provides additional control over the nature of the treated web. That is, the wet and dry tensile properties can be controlled by controlling variables such as the relative amounts of polyamines and polymeric anionic compounds, the order in which the polymer is added to the fiber feed, the pH of the fiber feed, the load ratio of the polymer, and the like. .

As used herein, a polymeric anionic compound is a polymer having repeating units containing two or more anionic functional groups that can be bonded to the hydroxyl groups of the cellulosic fibers. Such compounds can cause inter-fiber crosslinking between individual cellulose fibers. In one embodiment, the functional group is a carboxylic acid, anhydride group or salts thereof. In one embodiment, the repeating unit comprises two carboxylic acid groups on adjacent atoms, in particular adjacent carbon atoms, wherein the carboxylic acid groups can form cyclic anhydrides and especially 5-membered ring anhydrides. have. The cyclic anhydride forms ester bonds with the hydroxyl groups of the cellulose in the presence of cellulosic hydroxyl groups at high temperatures. Polymers comprising copolymers of maleic acid, terpolymers, block copolymers and homopolymers, including copolymers of acrylic acid and maleic acid, represent one embodiment. Polyacrylic acid and related copolymers may be useful in the present invention. In one embodiment, carboxyl functionality can be added to the polymer to form a polymeric anionic compound. For example, acrylic acid functionalities can be added to the glyoxylated polyacrylamide to form suitable polymeric anionic compounds. In another example, carboxymethylcellulose can be used. In one embodiment, the polymeric anionic compound is poly-1,2-diacid.

Exemplary polymeric anionic compounds include the ethylene / maleic anhydride copolymers described in US Pat. No. 4,210,489 (Markofsky), which is incorporated herein by reference. Other examples are vinyl / maleic anhydride copolymers and copolymers of epichlorohydrin and maleic anhydride or phthalic anhydride. Copolymers of maleic anhydride and olefins, including poly (styrene / maleic anhydride) anhydride, may also be contemplated. Copolymers and terpolymers of maleic anhydride may also be used. Examples of polymeric anionic compounds include maleic acid, vinyl, also known as BELCLENE @ DP80 (Durable Press 80) and Belclen @ DP60 (Durable Press 60) from FMC Corporation, Philadelphia, PA. Terpolymers of acetate and ethyl acetate.

Other important polymers include maleic anhydride-vinyl acetate polymers, polyvinyl methyl ether-maleic anhydride aerials such as Gantrez-AN119, available from International Specialty Products, Calvert City, Kentucky. Copolymer, isopropenyl acetate-maleic anhydride copolymer, itaconic acid-vinyl acetate copolymer, methyl styrene-maleic anhydride copolymer, styrene-maleic anhydride copolymer, methyl methacrylate-maleic anhydride copolymer Can be mentioned.

Other terminal anionic acid groups which may be present on the polymer include sulfonic acid, sulfinic acid, phosphonic acid and the like. In addition to the acid anhydrides described above, acid halides, i.e., R-COX polymers (where X is a halogen comprising fluorine, chlorine, bromine or iodine) can be used.

The polymeric anionic compound can have any viscosity as long as the compound can be added to the pulp feed. In certain embodiments, the polymeric anionic compound may or may not dissolve in water. In this particular embodiment, the polymeric anionic compound can be used with a cosolvent or otherwise allow time for solubilization at high pH before being added to the pulp feed.

The polymeric anionic compound according to the present invention may have any suitable molecular weight, but in one embodiment, the polymeric anionic compound has a relatively low molecular weight. For example, in one embodiment, carboxymethyl cellulose may be used having a molecular weight ranging from about 70,000 Daltons to about 700,000 Daltons. Other molecular weight ranges may also be included by the second component of the present strengthening system, but for example the molecular weight is greater than about 10,000 Daltons. In one embodiment, the second component can have a molecular weight of about 10,000 Daltons to about 10,000,000 Daltons. Molecular weight as used herein refers to the weight average molecular weight measured by gel permeation chromatography (GPC) or equivalent method.

The polymeric anionic compounds may be copolymers or terpolymers to enhance the flexibility of the molecules as compared to the homopolymer alone. The improved flexibility of the molecules can be confirmed by the reduced glass transition temperature measured by the differential scanning calorimeter.

Another useful aspect of the polymeric anionic compounds of the present invention is that relatively high pH values can be used to produce compounds that are more suitable for neutral and alkaline papermaking processes and more suitable for a variety of processes, machines and fiber types. . In particular, the solution of polymeric anionic compound may have a pH of greater than about 3, more specifically greater than about 4, even more specifically greater than about 6.5, in one embodiment greater than about 10. In fact, paper webs comprising a two-component strengthening system formed in alkaline conditions according to the present invention can have very high wet and dry tensile indices. For example, a paper web comprising a polyvinylamine and a polymeric anionic compound, including an acrylic acid functional two-component strengthening system expressed at a pH of about 6.8 or greater, may have a dry tensile index of about 18 Nm / g or greater. . Moreover, when the polyvinylamine component is added to the pulp slurry before the polymeric anionic component, the dry tensile index of the product may even be greater than about 20 Nm / g in one embodiment.

In addition, the two-component strengthening system of the present invention can provide temporary wet strength or permanent wet strength to the web by changing process conditions while using the same component. For example, in one embodiment, a two-component strengthening system capable of sequentially adding polymer anionic compounds comprising polyvinylamine and acrylic acid functionalities to the pulp slurry under alkaline conditions to provide permanent wet strength to the paper web. The same components as described above may be added to the pulp slurry under acidic conditions to provide temporary wet strength to the paper web.

Without wishing to be bound by theory, polyamine polymers containing amino groups react with polymeric anionic compounds, especially carboxyl groups, in solution to form a polymer electrolyte complex (often referred to as coacervate), which reacts upon heating to crosslink two molecules. It is thought that it can form an amide bond and leave a hydrophobic backbone. While other carboxyl groups on the polymeric anionic compound may form ester crosslinks with hydroxyl groups on cellulose, amino groups on the polyamine polymer may form hydrogen bonds with hydroxyl groups on cellulose, or may be added by enzyme or chemical treatment. Covalent bonds may be formed with functional groups on cellulose, such as aldehydes, or with carboxyl groups on cellulose, which may be provided by chemical treatments such as certain forms of bleaching or ozonation. The result is a treated web with the addition of crosslinks for wet and dry strength properties, which in certain embodiments may also exhibit a high degree of hydrophobicity due to the lack of hydrophilic groups on the reacted polymer.

In one embodiment, polymeric anionic compounds can be used with the catalyst. Examples of suitable catalysts for use with the polymeric anionic compound include any catalyst that increases the rate of bond formation between the polymeric anionic compound and the cellulose fiber. Useful catalysts include alkali metal salts of phosphorus containing acids, such as alkali metal hypophosphites, alkali metal phosphites, alkali metal polyphosphonates, alkali metal phosphates and alkali metal sulfonates. Particularly preferred catalysts include alkali metal polyphosphonates such as sodium hexametaphosphate and alkali metal hypophosphites such as sodium hypophosphite. Several organic compounds, including imidazole (IMDZ) and triethyl amine (TEA), are also known to act effectively as catalysts. Inorganic compounds such as aluminum chloride and organic compounds such as hydroxyethane diphosphoric acid may also promote crosslinking.

Other specific examples of effective catalysts are disodium acid pyrophosphate, tetrasodium pyrophosphate, pentasodium tripolyphosphate, sodium trimetaphosphate, sodium tetramethaphosphate, lithium dihydrogen phosphate, sodium dihydrogen phosphate and potassium dihydrogen phosphate.

When a catalyst is used to promote bond formation, the catalyst is typically present in an amount ranging from about 5 to about 100 weight percent of the polymeric anionic compound. The catalyst is present in an amount of about 25 to about 75 weight percent of the polymeric anionic compound. In one embodiment about 50% by weight of the polymeric anionic compound.

As described in more detail below, polymeric anionic compounds may be added to the fiber feed sequentially with the polyamine polymer using various processing techniques, depending on the particular application. For example, one or the other of the components may be added to the fiber feed first, the pH may change, the relative concentration may change, the loading density of the polymer may change, and the like.

In preparing a web from a fiber feed comprising a polyamine compound and a polymeric anionic compound two-component reinforcement system, the polyamine compound and the polymeric anionic compound may be used in any mass ratio. For example, the ratio of polyamine compound to polymeric anionic compound may be from about 0.01 to about 100, more specifically from about 0.1 to about 10, even more specifically from about 0.2 to about 5, most particularly from about 0.5 to about May be 1.5.

Polymeric aldehyde-functional compounds

In addition to polymeric anionic compounds, another class of compounds that can be used with polyamines according to the invention are polymeric aldehyde-functional compounds. The term "aldehyde-functional" means that the aldehyde group is not bound to another functional group that makes it nonreactive.

In one embodiment, polyamines can be combined with polymeric aldehyde-functional compounds in a papermaking feed to obtain improved physical and chemical properties in the resulting web. The polyaldehyde polymer may be electrically neutral or have a charge, such as an ionic polymer such as, for example, an anionic or cationic polyaldehyde polymer. While not wishing to be bound or bound by theory, it is believed that cationic polyaldehydes tend to remain on cellulose fibers having anionic properties. Polymeric aldehyde-functional compounds can include glyoxylated polyacrylamides, aldehyde-functional polysaccharides, and aldehyde functional cationic, anionic or nonionic starches. Exemplary materials include those disclosed in US Pat. No. 4,129,722 to Lovine et al., Which is incorporated herein by reference. An example of a commercially available soluble cationic aldehyde functional starch is Cobond ^(R ) 1000 sold by National Starch. The polymeric aldehyde-functional compound may have a molecular weight of at least about 10,000, more specifically at least about 100,000, more particularly at least about 500,000. Otherwise, the polymeric aldehyde-functional compound may have a molecular weight of less than about 200,000, for example less than about 60,000.

As a further example of an aldehyde-functional polymer for use in the present invention, an aldehyde-functional further comprising a carboxyl group as disclosed in dialdehyde guar, WO 01/83887 (Thornton et al., Published November 8, 2001). Sex wet strength additives, dialdehyde inulin; And 2002 3, corresponding to US application 99/18706, filed August 19, 1988 by Gear and Staib of Hercules, Inc., which is incorporated herein by reference. Dialdehyde-modified anionic and amphoteric polyacrylamides of WO 00/11046, published May 2; Aldehyde-containing surfactants such as those disclosed in US Pat. No. 6,306,249 to Galante et al., Issued October 23, 2001, may also be used.

When used in the present invention, the aldehyde-functional compound has at least about 5 m-eq aldehyde per 100 grams of polymer, more specifically at least about 10 m-eq, even more specifically at least about 20 m-eq, most specific Preferably about 25 m-eq per 100 grams of polymer.

In one embodiment, the polymeric aldehyde-functional compound is glyoxylated polyacrylamide, such as cationic glyoxylated polyacrylamide. Such compounds are manufactured by PAREZ 631 NC wet strength resins available from Cytec Industries of West Patterson, New Jersey, and Hercobond, a product of Hercules, Inc., Wilmington, Delaware. (HERCOBOND) 1366. Another example of glyoxylated polyacrylamide is Parez 745, which is glyoxylated poly (acrylamide-co-diallyl dimethyl ammonium chloride). In some cases it may be advantageous to use mixtures of high molecular weight and low molecular weight glyoxylated polyacrylamides.

The aforementioned cationic glyoxylated polyacrylamides have previously been used as wetting enhancers. In particular, these compounds are known as temporary wet strength additives. As used herein, the temporary wetting enhancer provides a product that, when introduced into a paper or tissue product, is exposed to water for about an hour when it is introduced into a paper or tissue product and maintains less than about 70% of its original wet tensile index. It is defined as resin. On the other hand, permanent wet strength agents provide products that remain exposed to water for a time of about 1 hour and maintain values above about 70% of their original wet tensile index. According to the present invention, it has been found that when glyoxylated polyacrylamide, known as transient wetting enhancer, is sequentially combined with a polyamine polymer in the pulp fiber feed, the combination of the two components can result in permanent wet strength properties. .

In this way, the wet strength properties of the paper product can be carefully controlled by adjusting the relative amounts of glyoxylated polyacrylamide and polyamine polymer, as well as other process variables described below.

As used herein, a "wetting enhancer" is a material used to immobilize bonds between fibers in the wet state. Typically, the means by which fibers are fixed together in paper and tissue products involves hydrogen bonds and sometimes a combination of hydrogen bonds and covalent and / or ionic bonds. As used herein, wet state will typically mean that the product is nearly saturated with water or other aqueous solutions, but substantially saturated with body fluids such as urine, blood, mucus, menstrual blood, diarrhea, lymph, and other body discharges. You may.

Any material that, when added to a paper web or sheet, results in an average wet geometric tensile strength to dry geometric tensile strength ratio of greater than about 0.1 on that sheet will be defined as a wet enhancer for the purposes of the present invention. As mentioned above, these materials are typically called permanent wet strength agents or temporary wet strength agents.

According to the present invention, various wetting enhancers can be used in combination with the polyamine polymer. In some applications, it has been found that temporary wetting enhancers in combination with polyamine polymers can result in compositions having permanent wet strength properties. In general, the wet enhancers that can be used according to the invention are cationic, nonionic or anionic. In one embodiment, the additive is not strongly cationic to reduce the repulsive force in the presence of cationic polyamines.

Another class of compounds that can be used with the polyamine polymers according to the invention are various anionic or noncationic (eg zwitterionic) surfactants. Such surfactants may include, for example, straight and branched sodium alkylbenzenesulfonates, straight and branched alkyl sulfates, and straight and branched alkyl ethoxy sulfates. If desired, two or more surfactants may be combined.

Formation method of two-component strengthening system

In one embodiment of the invention, the polyamine polymer is pulp fed together with a second component, such as a polymeric anionic compound or a polymeric aldehyde-functional compound, to provide various advantages to the web made from the pulp feed. Is added to the water. Importantly, the polyamine polymer and the second component are not mixed before being added to the pulp feed, nor are they added to the pulp feed at the same time.

After both components have been added to the feed, the web can be formed according to any standard web-forming method.

For illustrative purposes only, the addition of either the polyamine polymer or the second component to the fiber feed may be by one or a combination of the following methods:

Adding the compound directly to the fibrous slurry, such as injecting it into the slurry before entering the headbox. The slurry concentration may be about 0.2% to about 25%, specifically about 0.2% to about 10%, more specifically about 0.3% to about 5%, most specifically about 1% to about 4%.

Adding to individualized fibers. For example, finely divided or flash dried fibers may be placed in an air stream combined with aerosols or sprays of compounds to treat individual fibers before they are introduced into a web or other fibrous product.

The addition level can be about 0.5 to about 10 Kg per tonne of dry fiber for the second component of the polyamine polymer or system. For example, in one embodiment, both components can be added to the fiber feed in the same amount. For example, up to about 10 kG per ton of polyamine polymer may be added to the fiber feed, and the same addition level of the second component, i.e., up to about 10 kG / ton, may be added to the fiber feed. Can be. Otherwise, the components may be added in different amounts. For example, the ratio of polyamine added to the fiber feed to the second component may be between about 0.01 and about 100, for example about 0.1 to about 10, in one embodiment about 0.2 to about 5.

The second component of the polyamide polymer and system can be combined with cellulosic fibers at any pH, which in fact is one of the process variables that can be adjusted to match the impact on the product web of the two-component reinforcement system. One. For example, in certain embodiments, the pulp feed may have a pH adjusted to an acidic level of less than about 6 to produce a two-component strengthening system exhibiting transient wet strength in a web. In other embodiments, the temporary wet strength at higher pH levels can be improved using, for example, adjustment of other process variables such as the load density of the polyamine polymer, the relative amounts of the two components, the concentration of the polymer added to the feed, the order of addition, and the like. Can be generated on the web.

While not wishing to be bound by theory, the nature of the bond formed between the two components of the reinforcement system and the cellulose fibers of the pulp feed may depend in large part on the load ratio of the two-component composite, which in turn is dependent upon the load density and It is thought that it may depend on molecular weight.

The two components of the reinforcement system will be components that can form some bond between each other and the pulp fibers. For example, the components can form a composition in which they can act as a single reinforcing compound in the web, such as in bonds or otherwise associated with one another, such as through bond formation with fibers. Otherwise, one component or both components may predominantly bind the fiber and secondarily the other component, and this series of reactions may form a two-component reinforcement system.

The term "bond" is defined herein to include any form of chemical bond, such as, for example, covalent bonds, electrostatic bonds, coordination bonds, hydrogen bonds, and the like.

The components of the present reinforcement system may actually form bonds with each other and / or pulp fibers, but they may optionally bind due to electrostatic attraction or form a polymer electrolyte composite, which combines with the interaction with the pulp fibers. (Interaction or electrostatic interaction) to form the two-component strengthening system of the present invention. It is believed that two mechanisms are possible for this kind of combination. In the first mechanism, the first and second components of the system can form a polymer electrolyte composite in the pulp solution and then interact with the pulp fibers. The second mechanism is believed to include forming a layer of these components on individual pulp fibers. According to this mechanism, the components first added to the pulp slurry can be adsorbed onto the surface of the cellulose fiber (having a strong negative charge). This first coupling is very easy to introduce a flat arrangement. Then, once applied to the slurry, the second component is adsorbed onto the fiber over the first component due to the electrostatic attraction to the first component, the fiber surface, or a combination thereof. Various possible combinations of combinations and interactions may also appear in forming the strengthening system.

At first glance, the polyamine polymer of the above system may appear to not form a polymer electrolyte composite with a cationic or neutral polymer, but is not necessarily so. Complex formation occurs or does not occur can be calculated from the First Principle. Classical DLVO (Derjaguin-Landau and Vervey-Overbeek) theory states that complex formation occurs when the total potential of the interaction between two colloids (or polymer coils) is negative. The total potential of the interaction (V _tot ) is the sum of the two main components: electrostatic potential (V _el ) and van der Waals interaction (V _vw ). Thus, V _tot = V _el + V _vw (in particular applications, steric and hydrophobic potentials are often included). V _el may be a positive value (ie, repulsion) or negative value (ie, attractive force), depending on the component, and may be calculated from the Coulolombic equation. V _vw will always be negative and can be calculated by knowing the Hamaker constant. Thus, even for the same charge on the two components, V _tot may be negative and thus advantageous for the formation of the composite when the force due to van der Waals interaction is greater than the force due to electrostatic repulsion.

The examples that follow this description more clearly describe some specific wet strength properties that can be obtained in paper web products through various variations of process variables. Generally speaking, however, the main process variables that appear to affect the wet strength of the web are the ionic nature of the second component, the pH of the slurry when the component is added, the order of addition of the components, the relative ratios of the amounts of the two components, and the system. It is thought to be the amount of component added, the load ratio of the component (which may depend on the component's load density and molecular weight).

For example, when considering a handsheet containing a polyamine polymer and a two-component strengthening system comprising a cationic second component, the overall tissue strength properties may decrease with increasing pH of the system, but the strength of the strength may be With increasing, the desired balance between the strength permanence and the overall strength of the paper web can be obtained. In addition, adding the cationic component to the fiber slurry prior to the addition of the polyamine polymer can improve both the wet and dry strengths compared to those obtained in the reverse order of addition. Given the load density of the system, the two components are almost 1: 1 ratio and the polyamine is superior from the polyamine / cationic two-component system with a high level of load density (greater than about 15 m-eq per gram of polymer). Overall strength benefit can be obtained. This particular system can also provide permanent wet strength to the paper web.

Conversely, if the second component of the reinforcement system is anionic rather than cationic, paper webs with different overall strength properties can be produced, as well as similar variations in process parameters can have very different effects on the paper web. . For example, if the second component of a two-component system is anionic, adding a polyamine polymer to the fiber slurry prior to adding the second component may improve the overall strength properties of the product web, which contains a cationic second component. This is contrary to the strength characteristics of the paper web. This is considered to be because the anionic polymer cannot be adsorbed on the surface of the cellulosic fibers. Thus, if the anionic component is added first, then only after the polyamine component has been added the two components will bind with the fiber and possibly be associated with the fiber as a composite, whereas if the polyamine component is added first, it will Combine with the fiber prior to addition, and a layer of the component can be built up on the fiber surface. In addition, when the second component is anionic, the best overall strength properties of the paper web are such that when the polyamine polymer of the system is present in an amount greater than the second anionic component, for example, the ratio of polyamine polymer to anionic component is about 2 Obtained when it is from 1: 1 to about 5: 1.

Obviously, the two-component reinforcement system of the present invention can result in very different strength properties in paper webs made from fibers treated according to process parameters. This variability of the two-component strengthening system can provide a strengthening system that can be tailored to obtain a combination of specific strength properties in the paper web. For example, the paper web can be made to have the desired dry strength, wet strength, wet strength permanentity, etc. within a very narrow range through variations in the components that form the reinforcement system. More particularly, in contrast to the fixed and uniform reactivity of previously used reinforcing agents, which provided limited variability in the strength properties of the paper web into which the reinforcing agent was introduced, the two-component reinforcing systems of the present invention significantly reduced the reactivity of the system. It can be used to produce paper webs that provide extensive variability and have a wide range of strength properties. For example, if a paper web is desired to have a certain kind of strength characteristics, it is possible to provide a special system suitable for obtaining the desired product web by ordinary experiments using the two-component strengthening system of the present invention.

Since the two-component strengthening system of the present invention can be specifically tailored to provide a paper product with the desired strength properties, it is an undesirable process, for example, by increasing the level of chlorinated organic compounds in the waste stream of the papermaking process. It can be used in place of the conventionally known reinforcing agent including the reinforcing agent having the effect of By using the present invention, the level of such contaminants can be reduced or even removed from the waste stream. In order to reduce chlorinated organic compounds in the waste stream of the papermaking process, any paper manufacturing process using chlorinated enhancers, such as wetting enhancers derived from epichlorohydrin, may be considered. Complete or partial removal of the chlorinated reinforcement agent is carried out using the two-component reinforcement system of the present invention that is substantially or completely free of organo-chlorine over a period of time or steps such as one day or one week (at Introduction or stepwise over a period of time) may be performed by providing at least some or all of the wet or dry strength previously imparted by one or more chlorinated enhancers.

In one embodiment, the wet or dry strength of the paper product is maintained at a level at least before beginning the conversion to a two-component strengthening system. In another embodiment, the wet strength of the paper is at least about 90%, at least about 95%, or at least about 98% of the desired value before being converted to the two-component strengthening system. In one embodiment, conventionally used chlorinated organic wetting enhancers are completely removed from the combined components in the papermaking process, and the two-component system of the present invention is used instead. Wet-laid paper webs having a wet: dry tensile strength ratio of about 0.06 or more, more specifically about 0.08 or more, most specifically about 0.1 or more, such as 0.07 to 0.35, or about 0.1 to about 0.4, in one metric ton / Any papermaking process can be considered, such as a papermaking process for machines that produce more than one tpd. For machines or whole mills the production rate converted to a two-component strengthening system is much higher, for example about 10 tpd, 50 tpd, 100 tpd or 300 tpd or more. Without limitation, the paper web may include tissue, writing paper, linerboard, wrapping paper, paper intended for resin impregnation ("prepreg"), copy paper, lightweight coated paper, cardboard, card stock. cardstock, and the like. The paper may contain bleached or unbleached fibers or combinations thereof. In one embodiment, the paper fibers are substantially free of fibers bleached with molecular chlorine or chlorine dioxide. In one embodiment, the paper web produced has an ISO brightness higher than 80 or higher than 90. The basis weight of the web may be at least about 10 gsm, more specifically at least about 20 gsm, most particularly at least about 40 gsm. The concentration or absolute mass released per 24 hours of chlorinated organic species in the effluent stream of the production facility is at least 5%, at least 10%, by conversion to the two-component system of the present invention to reach the desired wet or dry strength level. Or 50% or more.

The two-component reinforcement system can selectively bind to one of a plurality of fiber types in the web and can be adsorbed or chemisorbed on the surface of one or more fiber types. For example, bleached kraft fiber may have a higher affinity for the two-component reinforcement system than synthetic fibers that may be present.

Preparation of Paper Webs for Use in the Present Invention

The fibrous web formed from the fibers treated in accordance with the present invention comprises diluting an aqueous aqueous fiber slurry onto a moving wire mesh to filter out the fibers and form an unfinished web, which includes a suction box, a wet compressor, a dryer device, and the like. It may be a wet-laid, such as a web formed by known papermaking techniques that are dehydrated by a combination of devices. Capillary dehydration may also be applied to remove moisture from the web.

Drying operations may include steam drying, such as drum drying, pass drying, superheated steam drying, alternative dehydration, Yankee drying, infrared drying, microwave drying, general radio frequency drying, and impact drying.

The moist fibrous web may be formed by a bubble forming process, wherein the fibers treated herein are applied to the unfinished web before bubbles are dehydrated or dried, whether the bubbles are loaded or suspended prior to dehydration.

For tissue webs, creped or uncreped manufacturing methods can be used. In the case of creped or uncreped methods, the unfinished tissue web may be imprinted against the deflection element before it is completely dried. The deflection element has a deflection conduit between the raised elements and the web is deflected into the deflection element by air pressure parallax to create a bulky dome, while the portion of the web present on the surface of the raised element is drier. It can be pressed against a surface to create a network of patterned areas that provide strength.

The fibrous web is generally a random plurality of papermaking fibers that can optionally be joined together with a binder. Any papermaking fiber as defined herein, or mixtures thereof, such as bleached fibers from kraft or sulfite chemical pulping processes can be used. Recycled fibers may also be used, such as cotton linters or papermaking fibers comprising cotton. Both high-yield and low-yield fibers can be used. In one embodiment, the fibers may be predominantly hardwood, such as at least 50% hardwood or at least about 60% hardwood or at least about 80% hardwood or substantially 100% hardwood. In another embodiment, the web is mainly softwood, such as at least about 50% softwood or at least about 80% softwood or about 100% softwood.

For many tissue applications, high brightness may be desirable. Thus, the papermaking fibers or paper obtained of the present invention may be at least about 60%, more specifically at least about 80%, more specifically at least about 85%, more particularly at least about 75% to about 90%, more particularly May have an ISO brightness of about 80% to about 90%, and even more specifically about 83% to about 88%.

The fibrous web of the present invention may be formed from a single layer or multiple layers. Both strength and softness are often obtained through layered tissue, such as webs with layers comprising hardwood or other fiber types, while at least one layer comprises softwood fibers. Structures with layers made by any method known in the art are within the scope of the present invention. In the case of multiple layers, the layers are generally placed side by side or in a face-to-face relationship, and all or part of the layers may be combined with adjacent layers. The paper web may also be formed from a plurality of separate paper webs, wherein the separate paper webs are formed from a single or multiple layers.

In preparing a structure having such a layer, the two-component strengthening system of the present invention may be present in one or more layers. For example, a two-component strengthening system can be present in a single layer of multiple layers or in a single layer of a multi-ply paper product. Otherwise, the two-component strengthening system of the present invention may be present in all layers of the multilayer article. In one embodiment of the present invention, the strengthening system may be present in two or more layers of the product and may be different in each layer. For example, while the same component is added to different layers of the product, the components may be added under different process conditions, i.e. under different order of addition, different pH, different concentration, etc., so that the influence of the strengthening system is different in different layers of the product. Can be. In another embodiment, the strengthening system of the present invention may be added to two or more layers of an article, but the components of the system may vary from layer to layer. For example, polyamine polymers having similar but different loading densities can be added to different layers to which the same second component has been added to tailor the strength properties of the layers. Countless variations of the multilayered paper product are considered so that the strength properties of each layer of the product, ie the strength properties of the product itself, can be specifically tailored.

When making a web with layers, the web uses one headbox with two or more layers, two or more headboxes for depositing a series of different feeds on one forming fabric, or separate forming cloths. The unfinished webs can be fabricated together ("couching") to form a multilayer web using two or more headboxes each depositing a feed onto it. Distinct feeds include components of reinforcement system, consistency, fiber type (e.g. eucalyptus vs softwood, or southern pine vs. northern pine), fiber length, bleaching method (e.g. peroxide bleaching versus chlorine dioxide bleaching), pulping method ( Eg kraft to sulfite pulping, or BCTMP to kraft), degree of purification, pH, zeta potential, color, Canadian standard degrees of freedom (CSF), particulate content, size distribution, synthetic fiber content (e.g., 10% polyolefin fibers Or layers with two-component fibers with denier less than 6), fillers (eg, plastic particles such as CaCO ₃ , talc, zeolites, mica, kaolin, powdered polyethylene, etc.), starches, antimicrobial additives, odor inhibitors, chelating agents , Chemical debonders, quaternary ammonia compounds, viscosity modifiers (eg CMC, polyethylene oxide, guar gum, xanthan gum, gum paste, okra extracts, etc.), silicone compounds, fluorinated polymers, light In the presence of additives such as brighteners enemy it may be differentiated by at least one. For example, in one embodiment, the reinforcement system of the present invention is added to the middle layer of a three layer web containing predominantly softwood fibers to improve the strength properties of the multilayer web, while the outer layers of the present invention Hardwood fibers may be contained predominantly without the addition of reinforcement systems to provide the desired softness in multilayer articles.

For example, a headbox with a useful layer may be a four-layer Beloit (III) headbox or a multi-mode Voith Sulzer (Ravensburg, Germany) ModuleJet ^(R) headbox. It may include. The principle of layering a web is described in US Pat. No. 4,225,382 (Kearney and Wells), issued September 30, 1980, which discloses the use of two or more layers to form a fold-separable tissue. . In one embodiment, the first and second layers are provided from slurry streams of different consistency. In another embodiment, the two well-bonded layers are separated by an inner barrier layer, such as a film of hydrophobic fibers, to improve fold separation.

In one embodiment of forming a multilayer web, the initial pulp suspension is divided into two or more fractions that differ in fiber properties such as average fiber length, percentage of particulates, percentage of carrier elements, and the like. In one embodiment, the complete initial pulp suspension may be treated according to the present invention prior to sorting. In another embodiment, the pulp suspension may be sorted first and then one or more fractions may be treated separately in accordance with the present invention. The sorting can be performed by any means known in the art, including sieves, filters, centrifugation, hydrocyclones, application of ultrasonic fields, electrophoresis, passage of suspension through spiral tubes or rotating plates, and the like. The sorted pulp stream may be treated in combination with additives or other fibers, or the concentration may be adjusted to a level suitable for paper formation, and then the stream containing the sorted fibers may be sent to a separate part of the layered headbox to produce a layered tissue product. Can be prepared. The sheet with the layer may have two, three, four or more layers. The two-layered sheet is such that the lighter layer has a mass of at least about 5%, or at least about 10%, at least about 20%, at least about 30%, at least about 40%, or at least about 50% of the basis weight of the entire web. It may have a split based on the layer basis weight. Exemplary weight percent splits for three-layer webs are about 20% / 20% / 60%; About 20% / 60% / 20%; About 37.5% / 25% / 37.5%; About 10% / 50% / 40%; About 40% / 20% / 40%; And about equivalent partitioning for each layer. In one embodiment, the ratio of the basis weight of the outer layer to the inner layer is about 0.1 to about 5; More specifically about 0.2 to about 3, still more specifically about 0.5 to about 1.5. The paper web with layers according to the invention can serve as a substrate sheet for dual printing crepe operations.

In another embodiment, the tissue web of the present invention may comprise a multilayer structure in which one or more layers have about 20% high yield fibers, such as CTMP or BCTMP. In one embodiment, the tissue web comprises a first reinforcing layer having cellulose fibers and a two-component reinforcement system of the present invention. The web also has a binder material, such as a synthetic fiber comprising at least about 20% by weight high yield fibers and optionally, thermally bonded bicomponent binder fibers, thus resulting in a bulky multilayer structure having good strength properties. And a second high yield layer.

The slurry comprising the polyamine polymer and the second component may also contain no formaldehyde or crosslinking agent which releases formaldehyde. In addition, using the strengthening system of the present invention eliminates the need for conventionally known permanent wet strength agents comprising these compounds, such as polyamide epichlorohydrin reinforcements, and therefore comprises a polyamine polymer and a second component. The slurry may not contain low molecular weight organic chlorinated compounds.

The two-component strengthening system of the present invention may be used with any known materials and chemicals that do not conflict with their intended use. For example, when used in the manufacture of fibrous materials in absorbent articles or other products, odor absorbers, activated carbon fibers and particles, baby powders, soda, chelating agents, zeolites, perfumes or other odor-masking agents, cyclodextrin compounds , Odor inhibitors such as oxidants and the like may be present. The absorbent article may also include metal phthalocyanine materials for odor suppression, antibacterial properties or other purposes. Superabsorbent particles, fibers or films may also be used. For example, an absorbent fibrous mat of finely divided fibers treated with the disclosed reinforcement systems may be combined with superabsorbent particles to act as an absorbent core or absorbent layer in disposable absorbent articles such as diapers. Various other compounds known in the paper and tissue making art can be included in the web of the present invention.

Debonders, such as quaternary ammonium compounds with alkyl or lipid side chains, can be used to provide a high wet: dry tensile strength ratio by lowering the dry strength without a correspondingly significant decrease in wet strength. Softening compounds, emollients, silicones, lotions, waxes and oils may have similar benefits in reducing dry strength, while providing enhanced tactile properties such as a soft, smooth feel. Fillers, fluorescent bleaches, antibacterial agents, ion-exchange compounds, odor-absorbers, dyes and the like can also be added.

Hydrophobic materials added to selected areas of the web, especially the outermost portion of the textured web, may be important for improved dry feel of articles intended for absorbency and removal of liquids close to the skin. Webs formed from fibers treated with a two-component reinforcement system can be further treated with waxes and emollients, typically by topical application. Hydrophobic materials may be applied over portions of the web.

When a debonder is applied, debonders (or softeners) known in the art can be used. Debonders may include silicone compounds, inorganic oils or other oils or lubricants known in the art, quaternary ammonium compounds having alkyl side chains, and the like. Exemplary debonders for use herein are cationic materials such as quaternary ammonium compounds, imidazolinium compounds, and other such compounds having aliphatic, saturated or unsaturated carbon chains. The carbon chain may be one or more chains which may be unsubstituted or substituted, for example with hydroxyl groups. Non-limiting examples of quaternary ammonium debonders useful herein include hexamethonium bromide, tetraethylammonium bromide, lauryl trimethylammonium chloride, and dihydrogenated dimethylammonium methyl sulfate.

Suitable debonders may include any number of quaternary ammonium compounds and other emollients known in the art, and include Prosoft, a product of Gold-6, or C-6001, which is a product of Goldscmidt or Wilmington, Delaware. Oleolimidazolinium debonders such as TQ-1003; Verocell 596 and 584 (quaternary ammonium compounds) from Eka Nobel Inc .; Adogen 442 (dimethyl dihydrogenated uji ammonium chloride) from Crrompont; Quasoft 203, a product of Quaker Chemical Company; Arquad 2HT75 (di (hydrogenated tallow) dimethyl ammonium chloride), a product of Akzo Chemical Company; Mixtures thereof, and the like, without limitation.

Other debonders include tertiary amines and derivatives thereof; Amine oxides; Saturated and unsaturated fatty acids and fatty acid salts; Alkenyl succinic anhydrides; Alkenyl succinic acid and the corresponding alkenyl succinate salts; Sorbitan mono-, di- and tri-esters including but not limited to stearate, palmitate, oleate, myristate and behenate sorbitan esters; And particulate debonders such as clay and silicate fillers.

In one embodiment, synergistic combinations of quaternary ammonium surfactant components and nonionic surfactants can be used.

The debonder may be added at a level of about 0.1% or more, specifically about 0.2% or more, more specifically about 0.3% or more based on the dry fibers. Typically, the debonder will be added at a level of active material of about 0.1 to about 6%, more typically about 0.2 to about 3%, based on the dry fibers. The percentage given in the amount of debonder is given as the amount added to the fiber, not as the amount actually held by the fiber.

Softeners known in the art of tissue making may also serve as debonders or hydrophobic materials suitable for the present invention, including fatty acids; Wax; Quaternary ammonium salts; Dimethyl dihydrogenated tallow ammonium chloride; Quaternary ammonium methyl sulfate; Carboxylated polyethylene; Cocamide diethanol amine; Coco betaine; Sodium lauroyl sarcosinate; Partially ethoxylated quaternary ammonium salts; Distearyl dimethyl ammonium chloride; Methyl-1-oleyl amidoethyl-2-oleyl imidazolinium methyl sulfate (Varisoft 3690, product of Witco Corporation, currently Crompton, Middlebury, CT); Mixtures thereof; And ones known in the art, and the like. Topical emollients, such as functional and non-functional organic polysiloxanes, such as polysiloxane materials known in the art, can be applied to the web to improve the surface feel of the article.

Debonder may be added to the web in the feed. However, the debonder may also be added to the web after formation of the wet-laid sheet. In one embodiment, the debonder can only avoid a bad reaction between the components and the debonder to the fiber having either the polyamine polymer or the second component of the system by suitable choice of temperature, pH value, contact time, etc. If present, it is added. The additive may be applied to the wet-laid sheet heterogeneously using one pattern or one application means, or using a separate pattern or application means. Heterogeneous application of chemical additives may be by gravure printing, spraying or any of the methods described above.

Surfactants may also be used in admixture with the polyamine polymer, either of the second components, or separately added to the web or fiber. Surfactants include Uji trimethylammonium chloride; Silicone amides; Silicone amido quaternary amines; Silicone amidazoline quaternary amines; Alkyl polyethoxylates; Polyethoxylated alkylphenols; Fatty acid ethanol amides; Dimethicone copolyol esters; Dimethiconol esters; Dimethicone copolyols; Mixtures thereof; It may be anionic, cationic or nonionic including, but not limited to, those known in the art.

In one embodiment, the paper webs of the present invention may be laminated with additional plies of tissue or layers made of nonwoven materials such as spunbond or meltblown webs, or other synthetic or natural materials.

The web may be calendered, embossed, cut, wetted again, wetted for use as a wet wipe, impregnated with thermoplastic or resin, treated with hydrophobic material, printed, punched, perforated, It may be converted into a multi-ply assembly, or it may be converted into a bath tissue, a facial tissue, a paper towel, a wipe, an absorbent article, or the like.

The tissue product of the present invention may be converted into any known tissue product suitable for consumer use. The transformation may be calendaring, embossing, cutting, printing, addition of perfumes, addition of lotions or hygiene additives such as emollients or methanol, preferably stacking the cut sheets in a paper box, production of rolls of finished products, suitable The final package may include introduction into a product or other product form, including enclosing the poly film with a picture printed thereon.

With reference now to various embodiments of the present invention, one or more embodiments are described below. Each example is provided by way of explanation of the invention, not as a limitation of the invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention.

Example 1 Control-Catiofast ^(R) , Parez ^(R) ) And Kymene ^(R) Of wet strength development

Preparation of Pulp Slurry

To prepare the pulp slurry, 24 grams (oven-dry basis) of pulp fibers were soaked in 2 liters of DI water for 5 minutes. The pulp slurry was decomposed for 5 minutes in a British cracker. The slurry was then diluted with 8 liter volume of water. A reinforcing agent was then added to the slurry. After addition of the reinforcing agent, the slurry was mixed for 10 minutes at normal shear force with a standard mechanical mixer.

Manufacture of hand sheet

Handsheets were made with a basis weight of 60 gsm. During handsheet formation, the appropriate amount of fiber (0.3% concentration) slurry needed to make a 60 gsm sheet was metered into the graduated cylinder. The slurry was then poured from a graduated cylinder into a 8.5-inch by 8.5-inch Valley handsheet mold (Valley Laboratory Equipment, Voith, Inc.) pre-filled with water to an appropriate level. After pouring the slurry into the mold, the mold was completely filled with water, including the water used to rinse the graduated cylinder. The slurry was then slowly stirred up and down seven times using a standard perforated mixing plate inserted in the slurry, followed by removal of the slurry. Water was drained from the mold through the wire assembly at the bottom of the mold to keep the fibers forming an unfinished web. The forming wire was a 90 × 90 mesh stainless-steel wire mesh. The web was transferred from the mold wire using two blotters placed on top of the web with the smooth side of the blotter in contact with the web. The blotter was removed, and the unfinished web was lifted using the lower blotter and attached thereon. The lower blotter was separated from the other blotter to keep the unfinished web attached to the lower blotter. The blotter was placed with the unfinished web facing up, and the blotter was placed on top of two other dry blotters. Two dry blotter papers were further placed on top of the unfinished web. The pile of blotter paper with the unfinished web was placed in a Valley hydraulic press and pressed for 1 minute at a pressure of 100 psi applied to the web. The compressed web was removed from the blotter paper and placed on a valley steam dryer containing water vapor at 2.5 psig pressure, with the wire-side surface of the web neighboring the metal drying surface and the felt tensioned on the opposite side of the web for 2 minutes. Heated during. Felt tension was provided by pulling down a weight of 17.5 pounds on one end of the felt extending beyond the edge of the metal dryer surface. The dried handsheets were trimmed 7.5 inches square using a paper shredder and weighed on a heated scale maintained at 105 ° C. to obtain the oven dry weight of the web. Next, dry and wet tensile tests were performed on the handsheets.

Three reinforcing agents were compared in this example: Parez ^(R ) 631NC (cationic glyoxylated polyacrylamide) from Cytec Industries; Catiofast ^(R) PR 8106 (polyvinylamine from BASF); And Kymene ( ^R) 557 LX (polyaminoamide-epichlorohydrin from Hercules Inc.). These additives were each added to the same feed in 1% aqueous solution and stirred for 10 minutes. The added-on levels investigated ranged from 0 to 10-kg / T (dry fibers). The pH of the slurry was maintained at neutral (6.8) at each cord. No additive was used in the control sample. The results are reported in Table 1 below.

Control Data-Effect of Wetting Enhancer Type and Concentration on Handsheet Properties (pH = 6.8) code polymer Concentration (Kg / T) Dry TI (Nm / g) Wet TI (Nm / g) Wet TI 1-hr (Nm / g) % Wet TI maintained after 1-hr % Wet / dry TI contrast - - 10.7 0.9 0.7 8% 74% One PVAm 2.5 10.9 1.6 1.5 94% 15% 2 PVAm 5 18.7 3.9 3.1 79% 21% 3 PVAm 10 15.6 3.8 3.1 81% 24% 4 C Parez ^(R) 2.5 14.3 1.9 1.2 63% 13% 5 C Parez ^(R) 5 16.5 2.3 1.4 31% 16% 6 C Parez ^(R) 10 22.5 4.1 2.7 66% 18% 7 Kemen ^(R) 2.5 14.1 3.4 3.0 88% 24% 8 Kemen ^(R) 5 17.5 5.8 4.7 81% 33% 9 Kemen ^(R) 10 20.6 7.9 6.1 77% 38%

Several things can be found from the data. First, for handsheets made with Catiofast ^(R) PR 8106, the wet handsheet strength does not change even if the dose level doubles from 5 to 10 kg / T (dry fiber). This phenomenon was not observed in the case of the Kymene ^(R) and Parez ^(R). While not wishing to be bound by theory, this property may be due to the high polymer loading that limits its adsorption performance. Secondly, while Parez ^(R) is the most efficient drying enhancer (code 6), chimen ^(R) is the most efficient wet strength resin (code 9) as it provides the highest wet strength and wet / dry strength ratio. Third, the chimen ^(R) , known as a permanent wetting enhancer, exhibits wet strength permanence in the range of 77-88% (code 7-9); Farez ^(R) , predominantly considered to be a temporary wet strength resin, expresses wet strength durability in the range of 63 to 66% (code 4-6). Catiofast ^(R) PR 8106, with wet strength permanence of 81-94% under the conditions used, was classified as a permanent wet enhancer with an initial wet strength similar to the Parez ^(R) 631NC.

Example 2: Influence of pH and Addition Sequence on PVAm / Cationic Parez Two-Component

A slurry of pulp fibers was prepared as described in Example 1. A two-component strengthening system was formed in the slurry comprising the following compounds:

1% aqueous solution of C Parez ^(R) 631NC (cationic glyoxylated polyacrylamide), manufactured by Cytec Industries

1% aqueous solution of catiofast ^(R) PR 8106 polyvinylamine

Polyvinylamine and Cfarrez ^(R) were added sequentially at a constant addition level at 10 Kg / T, respectively. The first polymer was added to the feed and stirred for 10 minutes. Next, a second polymer was added to the feed and mixed for 2 minutes. Handsheets were prepared and tested as in Example 1. The results (average five samples) are shown in Table 2. No additives were used for the control. The pH of the pulp feed was adjusted as shown in Table 2 below prior to the addition of the polymer.

Tensile data of handsheets treated with polyvinylamine / cationic fares. Effect of pH and Addition Sequence (10 Kg / T PVAm and 10 kg / T Parez) code First polymer added pH Dry TI (Nm / g) Wet TI (Nm / g) Wet TI 1-hr (Nm / g) % Wet TI maintained after 1-hr % Wet / dry TI contrast - 6.9 10.65 0.89 0.66 74.2% 8.36% 10 PVAm 6.8 20.79 5.26 3.98 75.7% 19.1% 11 Parez 631 6.8 30.43 7.85 5.61 71.5% 18.4% 12 PVAm 4 32.78 8.45 5.19 61.4% 15.8% 13 Parez 631 4 35.18 8.93 5.74 64.3% 16.3% 14 PVAm 10 21.13 3.58 2.67 74.6% 12.6% 15 Parez 631 10 29.52 6.48 4.85 74.8% 16.4%

Several things can be found from the data. First, the efficiency of the PVAm / C Farares system is a function of pH; Best wet and dry strengths were obtained at acidic pH (pH 4). The strength property of the tissue decreases with increasing pH of the system. Second, the efficiency of the PVAm / C Farares system is a function of the polymer addition order; Best wet and dry strengths were obtained when C Farrez was added first. Third, the wet strength permanence, and wet / dry strength ratio, defined as the ratio of wet strength after 1 hour soaking to wet strength measured immediately after soaking, can both be controlled by the order of pH and polymer addition. Fourth, the PVAm / C Farares system exhibits temporary wet strength with% wet TI, which remains in the range of 61% to 76% after 1 hour (code 10-15); This is in contrast to the nature of the PVAm itself (Code 1-3, Example 1).

Example 3: polyvinylamine / cationic fares ^(R)  Two-Component Enhancers-Effect of Polymer Ratio and Polyvinylamine Load Density

A slurry of pulp fibers was prepared as described in Example 1. A two-component strengthening system was formed in the slurry comprising the following compounds:

1% aqueous solution of C Parez ^(R) 631NC (cationic glyoxylated polyacrylamide), manufactured by Cytec Industries

1% aqueous solution of polyvinylamine

Polyvinylamine and Cfarrez ^(R) were added sequentially at a constant addition level at 10 Kg / T, respectively. C Farrez ^(R) was first added to the feed and stirred for 10 minutes. Polyvinylamine was then added to the feed and mixed for 2 minutes. Three kinds of PVAm were used: Catiofast ^(R) PR 8106 (90% amine, 21 m-eq amine / g polymer), Catiofast ^(R) PR 8087 (50% amine, 11 me-q / g ) And Catiofast ^(R) 8104 (10% amine, 2.3 m-eq / g). The total polymer concentration added to the feed was equal to 10 kg / T (dry fiber). The weight ratio of PVAm / C Farares ^(R) varied from 0: 1, 1: 5, 1: 2, 1: 1, 2: 1, 5: 1 and 1: 0. The pH of the slurry was maintained at neutral (6.8) at each cord. Handsheets were prepared and tested as in Example 1. The results (average five samples) are shown in Table 3. No additives were used for the control.

PVAm / C Farares ^(R) Two-Component Enhancers-Effect of Polymer Ratio and PVAm Load Density on Hand Sheet Properties (pH = 6.8, 10-kg / T Polymer Concentration) code % PVAm load density PVAm: C Farez ^(R) ratio Dry TI (Nm / g) Wet TI (Nm / g) Wet TI1-hr (Nm / g) 1-hr retention% wet TI % Wet / Dry TI % Elongation TEA @ max (J / m ² ) E (kgf) contrast --- 0: 0 10.7 0.9 0.7 8% 74% 0.9% 3.7 319 16 90% 0: 1 22.5 4.0 2.7 67% 18% 1.6% 15.0 467 17 90% 1: 5 28.3 5.9 3.9 67% 21% 1.8% 21.1 461 18 90% 1: 2 27.9 5.8 4.5 77% 21% 2.1% 25.1 429 19 90% 1: 1 29.2 6.5 4.7 72% 22% 1.7% 20.5 485 20 90% 2: 1 23.1 4.5 3.9 87% 19% 1.5% 14.1 577 21 90% 5: 1 24.5 5.1 4.1 80% 21% 1.5% 14.6 336 22 90% 1: 0 15.6 3.8 3.1 82% 25% 1.0% 6.3 374 23 50% 0: 1 22.5 4.0 2.7 67% 18% 1.6% 15.0 467 24 50% 1: 5 22.3 5.0 3.9 78% 22% 1.6% 14.9 436 25 50% 1: 2 19.2 4.2 3.3 78% 22% 1.3% 9.8 402 26 50% 1: 1 19.7 4.5 3.2 71% 23% 1.3% 10.8 428 27 50% 2: 1 18.9 4.5 3.5 78% 24% 1.2% 9.6 429 28 50% 5: 1 16.5 3.4 2.9 85% 21% 1.1% 7.0 420 29 50% 1: 0 12.8 2.1 1.6 79% 16% 1.0% 5.3 339 30 10% 0: 1 22.5 4.0 2.7 67% 18% 1.6% 15.0 467 31 10% 1: 5 20.1 3.3 2.1 65% 16% 1.5% 12.5 439 32 10% 1: 2 18.9 2.5 1.8 71% 13% 1.5% 12.1 408 33 10% 1: 1 17.6 2.6 1.5 58% 15% 1.2% 8.5 410 34 10% 2: 1 14.8 1.6 1.1 69% 11% 1.0% 5.7 375 35 10% 5: 1 14.7 1.3 0.9 67% 9% 1.1% 6.5 409 36 10% 1: 0 13.4 0.8 0.6 67% 6% 1.1% 5.4 269

Table 3 shows some trends as a result of both the polymer ratio and the PVAm loading density. First, as the load density (% amine) of PVAm increases, the dry and wet strength increases. Secondly, samples containing 50% or 90% load density PVAm had maximum wet strength at PVAm / C Farrez ^(R) ratios of 1: 5, 1: 2, 1: 1, 2: 1 and 5: 1. Represents a plateau. Samples containing PVAm with a load density of 10% show a decrease in wet strength as the concentration of PVAm increases and the concentration of C Parez ^(R) decreases. The wet strength of the sample (code 36) containing only PVAm at 10% load density is equivalent to the wet strength of the control sample containing no additives. Thus, the data suggest that adding PVAm with a load density of 10% gives little benefit of strength to the handsheet. Third, the wet strength persistence is greatest when the PVAm concentration exceeds C Parez ^(R) . However, the wet strength after soaking for 1 hour is most permanent for 1: 1 PVAm (90% load) / C Farares ^(R) sample (Code 19). Wet strength durability is in the range of 58% to 87%. Fourth, the wet / dry ratio is very constant (18-25%) for cords containing PVAm with 50% and 90% load densities. Fifth, the maximum elongation, TEA and E, decreases or remains constant as the PVAm / C Farares ^(R) ratio increases for codes containing PVAm with 10% and 50% load densities. For cords containing PVAm with 90% load, the maximum elongation and TEA have a maximum at a PVAm / C Farares ^(R) ratio of 1: 2 while the modulus of elasticity is maximum at 2: 1. Sixth, the PVAm / C Farez ^(R) two-component system efficiently expresses dry strength. Overall, the 1: 1 PVAm (90% loading) / C Farares ( ^R) ratio appears to be the best combination for both dry and wet strength properties.

Example 4: Polyvinylamine / C Farares ^(R)  Two-Component Enhancers-The Effect of Total Polymer Concentration

A slurry of pulp fibers was prepared as described in Example 1. A two-component strengthening system was formed in the slurry comprising the following compounds:

1% aqueous solution of C Parez ^(R) 631NC (cationic glyoxylated polyacrylamide), manufactured by Cytec Industries

1% aqueous solution of Catiofast ^(R) PR 8106 polyvinylamine (90% amine)

A solution of CParez ^(R) was first added to the feed and the feed was mixed for 10 minutes. A solution of Catiofast ^(R) PR 8106 was added to the feed a second time and the feed was mixed for 2 minutes. The ratio of PVAm / C Farares ^(R) added to the feed is kept constant at 1: 1, while the total polymer concentration is at 0, 2, 4, 6, 10 and 15 kg / T (dry fibers). Changed. The pH of the slurry was maintained at neutral (6.8) at each cord. Handsheets were prepared and tested as described in Example 1. The results are reported in Table 4.

Table 4 clearly shows that as the polymer concentration increases, the dry strength, wet strength and stiffness improve. Such improvement in properties is continuous over a defined range of polymer concentrations.

PVAm / C Farares ^(R) Two-Component Enhancer-Influence on the handsheet properties of polymer concentrations (pH = 6.8, PVAm / C Farares ^(R) ratio of 1: 1 90% load density) code Polymer concentration (kg / T) Dry TI (Nm / g) Wet TI (Nm / g) Wet TI1-hr (Nm / g) 1-hr post retention% wet TI % Wet / Dry TI % Elongation TEA @ max (J / m ² ) E (kgf) contrast 0 10.7 0.9 0.7 74% 8% 0.9% 3.7 319 37 2 13.5 1.5 1.0 69% 11% 1.1% 5.8 374 38 4 18.3 3.0 2.3 77% 17% 1.2% 9.1 459 39 6 25.6 5.2 3.7 72% 20% 1.8% 19.1 426 40 10 29.2 6.5 4.7 72% 22% 1.7% 20.5 485 41 15 36.9 7.9 5.8 73% 21% 2.7% 42.2 615

Example 5: Polyvinylamine / C farez ^(R)  Two-Component Enhancers-Effect of pH and Polyvinylamine Load Density

A slurry of pulp fibers was prepared as described in Example 1. A two-component strengthening system was formed in the slurry comprising the following compounds:

1% aqueous solution of C Parez ^(R) 631NC (cationic glyoxylated polyacrylamide), manufactured by Cytec Industries

1% aqueous solution of polyvinylamine

In this example, the first polymer added to the feed was C Farrez ^(R) , after which the feed was mixed for 10 minutes. Polyvinylamines added afterwards were catiofast ^(R) PR 8106 (90% amine, 21 m-eq / g load density), catiofast ^(R) PR 8087 (50% amine, 11 m-eq / g Load density), or Catiofast ^(R) PR 8104 (10% amine, 2.3 m-eq / g load density). The PVAm / C Farares ^(R) ratio and the total polymer concentration added to the feed were 1: 1 and 10 kg / T (dry fibers), respectively. The feed was mixed for 2 minutes after polyvinylamine was added. The pH of the slurry was changed between 3.5 and 10.0. Handsheets were prepared and tested as in Example 1. The results are reported in Table 5.

PVAm / C Farares ^(R) Two-Component Enhancers-Effect of pH and PVAm Load Density on Handsheet Properties (10-kg / T Polymer Concentration, 1: 1 PVAm / C Farrez ^(R) Ratio) code % PVAm load density pH Dry TI (Nm / g) Wet TI (Nm / g) Wet TI1-hr (Nm / g) 1-hr post retention% wet TI % Wet / Dry TI % Elongation TEA @ max (J / m ² ) E (kgf) contrast --- 6.8 10.7 0.9 0.7 74% 8% 0.9% 3.7 319 42 90% 3.5 26.3 5.4 3.2 59% 21% 2.0% 21.8 477 43 90% 3.9 27.9 5.8 3.2 55% 21% 1.8% 21.6 519 44 90% 7.5 29.2 6.5 4.7 72% 22% 1.7% 20.5 485 45 90% 10.0 25.6 5.9 3.9 67% 23% 1.6% 16.7 435 46 50% 3.5 27.0 4.8 3.3 69% 18% 1.8% 19.6 387 47 50% 6.8 19.7 4.5 3.2 71% 23% 1.3% 10.8 428 48 50% 10.0 21.9 4.5 2.7 60% 20% 1.4% 12.4 382 49 10% 3.7 20.1 3.7 2.1 56% 19% 1.4% 11.6 356 50 10% 6.8 17.6 2.6 1.5 58% 15% 1.2% 8.5 410 51 10% 10.0 16.2 1.7 1.1 67% 10% 1.1% 6.7 365

From Table 5, several general statements can be made regarding the effect of pH on feed load balance and subsequent wet strength properties at a 1: 1 polymer ratio:

i) Acidic conditions are beneficial for the Cparez ( ^R) / Catiofast ^(R) PR 8104 (10% amine) system.

ii) The pH does not appear to affect the wet handsheet strength of the CParez ^(R) / Catiofast ^(R) 8087 (50% amine) system.

iii) Neutral pH has a significant impact on the strength development of the Cfarez ^(R) / Catiofast ^(R) PR 8106 (90% amine) system. Under acidic conditions, the system is promising as a two-component temporary wet strength agent.

Example 6: Effect of pH and Sequence of Addition on PVAm / Anionic Parezes 2-Component

A slurry of pulp fibers was prepared as described in Example 1. A two-component strengthening system was formed in the slurry comprising the following compounds:

1% aqueous solution of anionic fares (glyoxylated polyacrylamide with acrylic acid functional group)

1% aqueous solution of catiofast ^(R) PR 8106 polyvinylamine

For all cords, polyvinylamine was added at 5 Kg / T and Afaraz was added at 2.5 Kg / T. The first polymer was stirred with the feed for 10 minutes; Then a second polymer was added and mixed for 2 minutes before the handsheet was prepared. Handsheets were prepared and tested as in Example 1. After formation, a tensile test is performed on the hand sheet and the results (average of five samples) are reported in Table 6. No additives were used for the control.

Tensile data for handsheets treated with polyvinylamine / anionic fares. Effect of pH and Order of Addition. The addition level is 5 Kg / T for PVAm 8106 and 2.5 Kg / T for anionic Parez. code Added first polymer pH Dry TI (Nm / g) Wet TI (Nm / g) Wet TI 1-hr (Nm / g) % Wet TI maintained after 1-hr % Wet / dry TI contrast - 6.9 10.65 0.89 0.66 74.2% 8.36 52 A fares 6.8 11.65 0.89 0.72 81 7.7 53 PVAm 6.8 24.2 5.1 4.1 80 21 54 A fares 6.8 18.4 3.2 2.8 88 17 55 PVAm 4 16.6 2.1 1.2 59 13 56 A fares 4 11.7 1.1 0.7 65 9 57 PVAm 10 21.0 4.0 3.4 85 19 58 A fares 10 19.4 3.3 2.8 87 17 59 PVAm 6.8 19.2 3.89 - - 20 60 PVAm 6.8 19.8 3.1 - - 16 61 PVAm 6.8 26.2 5.2 - - 20

Several things can be found from the data. First, Anionic Parez (A Parez) by itself does not improve the tissue strength properties (code 52). This is because it is not adsorbed on the pulp fibers. Second, the efficiency of the PVAm / A Parez system is a function of pH; Best wet and dry strengths were obtained at neutral pH (pH 6.8). Third, the efficiency of the PVAm / A Parez system is a function of the order of polymer addition; The best wet and dry strengths were obtained when PVAm was added first. The pH dependence of the system is a function of the order of polymer addition. PVAm / A Parez can be adsorbed as a polymer composite when non-adsorbable A Parez is introduced into the feed first, but multilayers can be prepared if adsorbent PVAm is added first. Third, the wet strength permanence, and wet / dry strength ratio, defined as the ratio of wet strength after soaking for 1 hour to that measured immediately after soaking, can both be controlled by the order of pH and polymer addition.

Example 7: Influence of Anionic Polymer and Polymer Concentration in PVAm / Anionic Polyelectrolyte Bi-component System

A slurry of pulp fibers was prepared as described in Example 1. A two-component strengthening system was formed in the slurry comprising the following compounds:

Aqueous solution of anionic polyelectrolyte

1% aqueous solution of polyvinylamine (BASF Catiofast ^(R) PR 8106)

Two types of polymer electrolytes were compared: anionic parez (glyoxylated polyacrylamide with acrylic acid functionality) and low molecular weight (200,000) high load poly (acrylamide-co-acrylic acid) (20 wt% acrylamide). In all cases BASF Catiofast ^(R) PR 8106 polyvinylamine was used with anionic polyelectrolyte (PVAm). For all cords, polyvinylamine was first added in 1% solution and stirred with the feed for 10 minutes; The anionic polymer was then added at various concentrations and mixed for 2 minutes before preparing the handsheet as described in Example 1. After formation, a tensile test is performed on the hand sheet and the results (average of five samples) are reported in Table 7.

Tensile data for handsheets treated with polyvinylamine / anionic fares and polyvinylamine / polyacrylic acid (PAA). Influence of the type and polymer concentration of the anionic polymer (PAA or Afaraz). PVAm is added first, pH = 6.8. code PVAm concentration (Kg / T) Anionic polymer Anionic Polymer Concentration (Kg / T) Dry TI (Nm / g) Wet TI (Nm / g) % Wet / Dry TI contrast - - 10.65 0.89 8.36 62 5 PAA 2.5 19.2 3.89 20 63 5 PAA 5 19.8 3.1 16 64 5 PAA 10 26.2 5.2 20 65 5 A fares 2.5 26.3 5.2 20 66 5 A fares 5 21.8 4.9 22 67 5 A fares 10 19.7 4.2 21 68 2.5 A fares 2.5 17.4 2.9 17 69 2.5 A fares 5 18.7 3.7 20 70 2.5 A fares 10 18 3.4 19

Several things can be found from the data. First, for PVAm / PAA system at neutral pH both handsheet wet strength and dry strength both increase with increasing concentration of PAA (codes 62, 63 and 64). Code 64 has similar properties to Code 65, suggesting that no aldehyde groups are needed on the polymer to develop strength. Second, for PVAm / A Parez systems at neutral pH, both handsheet wet strength and dry strength decrease with increasing concentration of A Parez (codes 64, 65 and 66). Code 65 provides the highest tissue strength at the lowest polymer concentration; This suggests that the aldehyde functionality of Afarez is accompanied by a synergistic increase in strength.

Example 8 Polyvinylamine / carboxymethyl Cellulose Bi-Component Enhancer-Influence of Polymer Ratio

A slurry of pulp fibers was prepared as described in Example 1. A two-component strengthening system was formed in the slurry comprising the following compounds:

Carboxy Methyl Cellulose (CMC) (Mw 250,000 Daltons)

1% aqueous solution of polyvinylamine (BASF Catiofast ^(R) PR 8106)

For CMC the degree of substitution was about 0.65 to 0.9. In this study, CMC was added first followed by PVAm. The total polymer concentration was maintained at 10 kg / T (dry fiber). pH was maintained at 6.8. Handsheets were prepared as described in Example 1.

The effect of the polymer ratio on the handsheet properties is shown in Table 8. At a constant polymer concentration of 10 kg / T (dry fiber), controlling the PVAm / CMC ratio affects each property of interest. Maximum strength properties were obtained at PVAm / CMC ratios between 5: 1 and 2: 1 (codes 72-73). The data show that expression of strength does not necessarily require chemical interactions between amine (PVAm) and aldehyde (C Farrez ^(R) ) functional groups.

PVAm / CMC Two-Component Enhancer-Effect of Polymer Ratio (pH = 6.8, 10-kg / T Polymer Concentration, CMC Added First) code PVAm: CMC ratio Dry TI (Nm / g) Wet TI (Nm / g) Wet TI1-hr (Nm / g) 1-hr post retention% wet TI % Wet / Dry TI % Elongation TEA @ max (J / m ² ) E (kgf) contrast - 10.16 0.79 0.61 77 8 0.82 3.32 338 71 1: 0 14.02 3.65 3.01 82 26 0.92 5.13 387 72 5: 1 19.99 6.2 5.17 83 31 1.52 12.64 416 73 2: 1 22.54 5.79 5.03 87 26 1.64 15.26 407 74 1: 1 19.69 3.84 2.88 75 20 1.43 11.71 465 75 1: 2 12.99 1.37 1.21 88 11 0.93 4.82 376 76 1: 5 10.90 0.72 0.66 92 7 0.88 3.89 342 77 0: 1 11.28 0.78 0.52 66 7 0.78 3.44 370

Example 9 Polyvinylamine / carboxymethyl Cellulose Two-Component Enhancer-Influence of Polymer Addition Order

A slurry of pulp fibers was prepared as described in Example 1. A two-component strengthening system was formed in the slurry comprising the following compounds:

Carboxymethyl cellulose (CMC) of medium molecular weight (Mw 250,000 Daltons)

1% aqueous solution of polyvinylamine (BASF Catiofast ^(R) PR 8106)

The components had a PVAm / CMC ratio of 2: 1. For CMC the degree of substitution was about 0.65 to 0.9. In this study, each polymer served as an initial load on the feed. In addition, polymer electrolyte complexes were prepared at defined ratios for single load applications. The total polymer concentration was maintained at 10 kg / T (dry fiber). pH was maintained at 6.8. Handsheets were prepared and tested as described in Example 1.

The impact of the polymer addition order on the handsheet properties is summarized in Table 9. The order of polymer addition has a significant impact on handsheet properties. Best wet strength results were obtained by sequential polymer addition and first added CMC.

PVAm / CMC Two-Component Enhancer-Effect of Polymer Addition Order (pH = 6.8, 10-kg / T Polymer Concentration, PVAm / CMC Ratio = 2/1) code First polymer Dry TI (Nm / g) Wet TI (Nm / g) Wet TI1-hr (Nm / g) 1-hr post retention% wet TI % Wet / dry TI % Elongation TEA @ max (J / m ² ) E (kgf) 78 PVAm 20.83 4.81 3.75 78 23 1.72 15.24 483 79 CMC 21.76 5.69 4.54 80 26 1.62 14.60 505 80 Complex 14.47 2.88 2.7 94 20 1.05 6.03 394

Example 10 Polyvinylamine / Carboxy Methyl Cellulose Bi-Component Enhancer-Influence of Polymer Concentration

A slurry of pulp fibers was prepared as described in Example 1 except that a two-component reinforcement system comprising the following compounds was formed in the slurry:

Carboxymethyl cellulose (CMC) of medium molecular weight (Mw 250,000 Daltons)

Aqueous solution of polyvinylamine (BASF catiofast ^(R) PR 8106)

The components were used in combination at a PVAm / CMC ratio of 2: 1. For CMC the degree of substitution was about 0.65 to 0.9. In this study, the CMC component was first added to the feed, the feed was mixed for 10 minutes, then polyvinylamine was added to the feed, and the feed was mixed for an additional 2 minutes. The pH was maintained at 6.8 and the total polymer concentration in the feed changed for different codes. Handsheets were prepared and tested as described in Example 1.

The effect of total polymer concentration on handsheet properties is summarized in Table 10. Wet strength, dry strength, wet / dry strength ratio, toughness and stiffness increase as a function of polymer total concentration. Wet strength permanence is independent of polymer concentration, but similar to the reaction of chimen ^(R) .

PVAm / CMC Two-Component Enhancer-Effect of Polymer Concentration (pH = 6.8, PVAm / CMC Ratio = 2/1, CMC Added First) code Polymer concentration (mg / g) Dry TI (Nm / g) Wet TI (Nm / g) Wet TI1-hr (Nm / g) 1-hr post retention% wet TI % Wet / Dry TI % Elongation TEA @ max (J / m ² ) E (kgf) contrast 0 10.14 0.85 0.69 81 8 0.83 3.34 338 81 2 12.65 1.64 1.39 85 13 0.87 4.42 422 82 4 15.43 3.10 2.58 83 20 1.12 7.05 440 83 6 17.39 3.63 3.14 87 21 1.33 9.80 456 84 10 22.54 5.79 5.03 86 26 1.64 15.26 407 85 15 23.92 6.66 5.49 82 28 1.64 16.16 488

Example 11 Chitosan / C Farares ^(R)  2-component enhancers

Pulp fibers as described in Example 1 except that 50 g (oven-dry basis) of pulp fibers were immersed in 8 liters of deionized water for the fiber feed used to form a handsheet having a concentration of 0.625%. A slurry of was prepared. A two-component strengthening system was formed in the slurry comprising the following compounds:

Chitosan (natural polysaccharide containing primary amine functionality)

1% aqueous solution of Parez ^(R) 631NC (cationic glyoxylated polyacrylamide), manufactured by Scitech Industries

The use of chitosan as a dry and wet strength additive in papermaking is recorded. The first component was added to the feed, the feed was mixed for 10 minutes, the second component was added to the feed, and the feed was further mixed for 2 minutes. The pH remained neutral. Handsheets were prepared and tested as described in Example 1. When added to the feed with glyoxylated polyacrylamide (cationic fares 631NC), sheet properties similar to those of the polyvinylamine / cationic fares system were obtained. In other words, synergistic strength was dependent on the order of addition of the two materials. This may suggest that this action occurs with almost any polymeric amine and aldehyde combination. Data for chitosan and glyoxylated polyacrylamide sheets are shown in Table 11 below.

Chitosan / fares reinforcement meter code Farez (Kg / T) Chitosan (Kg / T) Dry TI (Nm / g) % Growth rate for control (dry TI) Wet TI (Nm / g) % Increase over control (wet TI) 86 0 0 15.5 0% 0.9 0% 87 5 0 19.9 29% 3.2 239% 88 10 0 24.3 57% 4.9 420% 89 0 5 15.6 One% 1.5 59% 90 0 10 16.9 9% 2.0 116% 91 5 5 19.1 23% 3.3 252% Chitosan is added first 92 10 10 26.5 71% 5.0 427% Chitosan is added first 93 5 5 27.2 76% 5.4 476% Paréz is added first 94 10 10 34.9 126% 7.7 720% Paréz is added first

It will be appreciated that the foregoing embodiments given for purposes of illustration are not intended to limit the scope of the invention. While only a few exemplary embodiments of the invention have been described in detail above, those skilled in the art will readily recognize that many modifications may be made to the exemplary embodiments without substantially departing from the new teachings and advantages of the invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the following claims and their equivalents. Also, while many embodiments may be contemplated that do not achieve all the advantages of some embodiments, the absence of a particular advantage should not necessarily be taken to mean that such embodiments are outside the scope of the present invention.

Claims (83)

Providing a slurry of pulp fibers; Adding to said slurry of pulp fibers a first component comprising a polymer having at least about 1.5 m-eq primary amine functionality per gram of polymer and having a molecular weight of at least about 10,000 Daltons; Adding a second component selected from the group consisting of a polymeric anionic compound and a polymeric aldehyde functional compound to a slurry of pulp fibers separately from the first component; Depositing a slurry of pulp fibers containing said first and second components onto said forming fabric; And Drying the slurry of pulp fibers to form a paper web, wherein the first and second components form a two-component reinforcement system in the paper web. The method of claim 1 wherein the first and second components form a polymer electrolyte composite in a slurry of pulp fibers. The method of claim 1 wherein the first and second components are bonded to each other in a two-component strengthening system. 4. The method of claim 3 wherein the first and second components can form covalent bonds with each other. The method of claim 1 wherein said first component is polyvinylamine. 6. The method of claim 5, wherein said polyvinylamine comprises vinylformamide units and at least about 50% thereof is hydrolyzed to provide amine functionality. 6. The method of claim 5, wherein said polyvinylamine comprises vinylformamide units, at least about 70% of which is hydrolyzed to provide amine functionality. The method of claim 1 wherein said first component is a polysaccharide having a primary amine functional group. The method of claim 1 wherein the first component is added to the slurry of pulp fibers before the second component. The method of claim 1 wherein the first component is added to the slurry of pulp fibers later than the second component. The method of claim 1 wherein said second component comprises a cationic polymer aldehyde functional compound. 12. The method of claim 11, wherein said second component comprises glyoxylated polyacrylamide. The method of claim 1, further comprising adjusting the pH of the pulp fiber slurry to a pH lower than about 6. 6. The method of claim 1 wherein the first component comprises at least about 11 m-eq primary amine per gram of polymer. The method of claim 1 wherein said first component comprises at least about 15 m-eq primary amine per gram of polymer. The method of claim 1, wherein the paper web maintains less than about 70% of the initial wet tensile index after soaking in water for about 1 hour. The method of claim 1, wherein the paper web maintains greater than about 70% of the initial wet tensile index after soaking in water for about 1 hour. The method of claim 1 wherein the first and second components are added to the slurry of pulp fibers in a ratio of about 5: 1 to about 1: 5. The method of claim 1, further comprising adjusting the pH of the pulp fiber slurry to a pH higher than about 6. 6. The method of claim 1 wherein said second component comprises a polymeric anionic compound having a carboxyl functional group. The method of claim 1, wherein the first component comprises a polymer having at least about 10 m-eq primary amine functionality per gram of polymer and having a molecular weight of at least about 20,000 Daltons.  A first component comprising a polymer having at least about 1.5 m-eq primary amine functionality per gram of polymer and having a molecular weight of at least about 10,000 Daltons, and a second selected from the group consisting of polymeric anionic compounds and polymeric aldehyde functional compounds A two-component reinforcement system for a paper web, comprising a component, wherein the two-component reinforcement system is expressed in a slurry of pulp fibers after the first and second components are sequentially added to the slurry. 23. A bicomponent strengthening system as defined in claim 22, wherein the first component comprises polyvinylamine. 23. A bicomponent strengthening system as defined in claim 22, wherein the first component comprises a polysaccharide having a primary amine function. 23. A bicomponent strengthening system as defined in claim 22, wherein the first component is added to the slurry of pulp fibers before the second component. 23. A bicomponent strengthening system as defined in claim 22, wherein the first component is added to the slurry of pulp fibers later than the second component. 23. A bicomponent strengthening system as defined in claim 22, wherein the second component comprises a cationic polymeric aldehyde functional compound. 28. A bicomponent strengthening system as defined in claim 27, wherein the second component comprises glyoxylated polyacrylamide. 23. The bicomponent strengthening system of claim 22, wherein the bicomponent strengthening system is expressed in a slurry of pulp fibers at a pH lower than about 6. 23. A bicomponent strengthening system as defined in claim 22, wherein the first and second components form a polymer electrolyte composite in a slurry of pulp fibers. 23. A bicomponent strengthening system as defined in claim 22, wherein the first and second components are bonded to each other. 32. A bicomponent strengthening system as defined in claim 31, wherein the first and second components can form covalent bonds with each other. 23. The bicomponent strengthening system of claim 22, wherein the first component has greater than about 11 m-eq primary amine per gram of polymer. 23. The bicomponent strengthening system of claim 22, wherein the first component has greater than about 15 m-eq primary amine per gram of polymer. 23. The bicomponent strengthening system of claim 22 comprising the first and second components in a ratio of about 5: 1 to about 1: 5 with respect to each other. 23. A bicomponent strengthening system as defined in claim 22, wherein the second component comprises a polymeric anionic compound having a carboxyl functional group. 23. A bicomponent strengthening system as defined in claim 22, wherein the second component comprises carboxymethyl cellulose. 23. The bicomponent strengthening system of claim 22, wherein the bicomponent strengthening system is expressed in a slurry of pulp fibers at a pH higher than about 6. 23. A bicomponent strengthening system as defined in claim 22, which provides a temporary wet strength for the paper web. 23. A bicomponent strengthening system as defined in claim 22, wherein the bicomponent strengthening system provides permanent wet strength for the paper web. 23. The bicomponent strengthening system of claim 22, wherein the first component comprises a polymer having at least about 10 m-eq primary amine functionality per gram of polymer and having a molecular weight of at least about 20,000 Daltons. 23. A bicomponent strengthening system as defined in claim 22, wherein the first component comprises a polyvinylamine polymer comprising partially hydrolyzed polyvinylformamide. 43. The bicomponent strengthening system of claim 42 wherein the degree of hydrolysis of the polyvinylformamide is at least about 50%. 43. The bicomponent strengthening system of claim 42 wherein the degree of hydrolysis of the polyvinylformamide is at least about 70%. 43. A bicomponent strengthening system as defined in claim 42, wherein the degree of hydrolysis of the polyvinylformamide is at least about 90%. Providing a paper making process comprising forming a slurry of pulp fibers and adding chlorinated reinforcement to the paper; Removing the addition of the chlorinated enhancer in the paper making process; Adding to said slurry of pulp fibers a first component comprising a polymer having at least about 1.5 m-eq primary amine functionality per gram of polymer and having a molecular weight of at least about 10,000 Daltons; Adding a second component selected from the group consisting of a polymeric anionic compound and a polymeric aldehyde functional compound to a slurry of pulp fibers separately from the first component; Depositing a slurry of pulp fibers containing said first and second components onto said forming fabric; And Drying the slurry of pulp fibers to form a paper web and forming a two-component reinforcement system in which the first and second components replace the chlorinated reinforcement agent in the paper web. To reduce the amount of incorporated low molecular weight organic compounds. 47. The method of claim 46, wherein said chlorinated enhancer comprises a polyamide-epichlorohydrin enhancer. 47. The method of claim 46, wherein said first component comprises polyvinylamine. 49. The method of claim 48, wherein said polyvinylamine has at least about 50 mole percent vinylamine per gram of polyvinylamine. 49. The method of claim 48, wherein said polyvinylamine has at least about 70 mole percent vinylamine per gram of polyvinylamine. 47. The method of claim 46, wherein said first component comprises a polysaccharide having a primary amine function. 47. The method of claim 46, wherein the first component is added to the slurry of pulp fibers before the second component. 47. The method of claim 46, wherein the first component is added to the slurry of pulp fibers later than the second component. 47. The method of claim 46, wherein said second component is a cationic polymeric aldehyde functional compound. 55. The method of claim 54, wherein said second component is glyoxylated polyacrylamide. 47. The method of claim 46 further comprising adjusting the pH of the slurry of pulp fibers to a pH lower than about 6. 47. The method of claim 46, further comprising adjusting the pH of the slurry of pulp fibers to a pH higher than about 6. 47. The method of claim 46, wherein said first component has greater than about 11 m-eq primary amine per gram of polymer. 47. The method of claim 46, wherein said first component has greater than about 15 m-eq primary amine per gram of polymer. 47. The method of claim 46, wherein the first and second components are added to the slurry of pulp fibers in a ratio of about 5: 1 to about 1: 5. 47. The method of claim 46, wherein said second component comprises a polymeric anionic compound having a carboxyl functional group. A paper web formed from a slurry of papermaking fibers; And A first component comprising a polymer having at least about 1.5 m-eq primary amine functionality per gram of polymer and having a molecular weight of at least about 10,000 Daltons, and a second selected from the group consisting of polymeric anionic compounds and polymeric aldehyde functional compounds A paper product comprising a component, wherein the first component and the second component are added sequentially to a slurry of papermaking fibers. 63. The paper product of claim 62, wherein the paper web has a bulk greater than about 2 cc / g. 63. The paper product of claim 62, wherein the first component comprises a polymer having at least about 10 m-eq primary amine functionality per gram of polymer and having a molecular weight of at least about 20,000 Daltons. 63. The paper product of claim 62, wherein the paper web maintains less than about 70% of the initial wet tensile index after soaking in water for about 1 hour. 66. The paper product of claim 65, wherein the paper web has a dry tensile index greater than about 22 Nm / g. 66. The paper product of claim 65, wherein the paper web has a dry tensile index greater than about 25 Nm / g. 66. The paper product of claim 65, wherein the paper web has a wet tensile index of less than about 2 Nm / g after soaking in water for about 1 hour. 66. The paper product of claim 65, wherein the paper web maintains less than about 60% of the initial wet tensile index after soaking in water for about 1 hour. 63. The paper product of claim 62, wherein the paper web maintains greater than about 70% of the initial wet tensile index after soaking in water for about 1 hour, and wherein the paper web does not include a polyamine epichlorohydrin reinforcement. 73. The paper product of claim 70, wherein the paper web has a dry tensile index of greater than about 20 Nm / g. 72. The paper product of claim 71, wherein the paper web has a dry tensile index of greater than about 25 Nm / g. The paper product of claim 70, wherein the paper web maintains greater than about 80% of the initial wet tensile index after soaking in water for about 1 hour. 63. The paper product of claim 62, wherein the first component comprises polyvinylamine. 63. The paper product of claim 62, wherein the first component comprises a polysaccharide having a primary amine function. 63. The paper product of claim 62, wherein the second component comprises a cationic polymeric aldehyde functional compound. 77. The paper product of claim 76, wherein the second component comprises glyoxylated polyacrylamide. 63. The paper product of claim 62, wherein the second component comprises a polymeric anionic compound having a carboxyl functional group. 63. The paper product of claim 62, wherein the second component comprises carboxymethyl cellulose. 63. The paper product of claim 62, wherein the paper product has a volume greater than about 5 cc / g. 63. The paper product of claim 62, wherein the paper product has a basis weight of about 5 to about 200 gsm. 63. The paper product of claim 62, wherein the two-component reinforcement system comprises a multilayer paper web added to one or more layers of the paper web. 83. The paper product of claim 82, wherein the multilayer paper web comprises a layer comprising softwood pulp and a layer comprising hardwood pulp, wherein the two-component reinforcement system is added to the layer comprising softwood pulp.